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Synthesis
Journal Prestige (SJR): 0.974  Citation Impact (citeScore): 2 Number of Followers: 53  Hybrid journal (It can contain Open Access articles)ISSN (Print) 0039-7881 - ISSN (Online) 1437-210X Published by Thieme Publishing Group  [233 journals]
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A 5 star rating indicates the linked pre-print has the exact same content as the published article.Synthesis 2023; 55: V-
DOI: 10.1055/s-0040-1720092
Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany
Artikel in Thieme eJournals:
Synthesis 2023; 55: V-2023-09-27T15:10:25+01:00
Inhaltsverzeichnis
Issue No: Vol. 55, No. 20 (2023)
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- SYNFORM ISSUE 2023/10
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A 5 star rating indicates the linked pre-print has the exact same content as the published article.Synthesis 2023; 55: A167-A180
DOI: 10.1055/s-0040-1720611
Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany
Artikel in Thieme eJournals:
Synthesis 2023; 55: A167-A1802023-09-26T13:04:30+01:00
Inhaltsverzeichnis
Issue No: Vol. 55, No. 19 (2023)
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- Linked PDF of Table of Contents
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A 5 star rating indicates the linked pre-print has the exact same content as the published article.Synthesis 2023; 55: VI-
DOI: 10.1055/s-0040-1720091
Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany
Artikel in Thieme eJournals:
Synthesis 2023; 55: VI-2023-09-07T09:18:54+01:00
Inhaltsverzeichnis
Issue No: Vol. 55, No. 19 (2023)
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- Editorial
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A 5 star rating indicates the linked pre-print has the exact same content as the published article.Synthesis 2023; 55: III-
DOI: 10.1055/s-0040-1720088
Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany
Artikel in Thieme eJournals:
Synthesis 2023; 55: III-2023-09-07T09:16:44+01:00
Inhaltsverzeichnis
Issue No: Vol. 55, No. 19 (2023)
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- Palladium/Charcoal-Catalysed Olefin Reduction for the Simple and Efficient
Synthesis of Substituted gem-Diborylalkanes-
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Authors: Das; Kanak Kanti, Ghorai, Debraj, Mahato, Somenath, Panda, Santanu
Abstract: gem-Diborylalkanes have recently emerged as valuable synthons for diverse C–C bond-forming reactions. They represent an important class of bifunctional reagents that can be applied for the synthesis of simple to complex skeletons. Herein, we report a Pd-catalysed hydrogenation method for the synthesis of gem-diborylalkanes from the corresponding gem-diborylalkenes, which are themselves prepared from the corresponding aldehydes and ketones using known procedures. In addition, transformations of two representative gem-diborylalkane products are discussed leading to a range of functionalised derivatives.
Citation: Synthesis ; : -
PubDate: 2023-09-28T16:00:40+01:00
DOI: 10.1055/a-2147-1336
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- Recent Advances on High-Order Dipolar Annulations of Donor–Acceptor
Cyclopropanes/Cyclobutanes-
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Authors: Yang; Liangliang, Wang, Haiyang, Lang, Ming, Peng, Shiyong
Abstract: This short review summarizes the recent impressive developments on the high-order dipolar annulations (HODAs) of donor–acceptor cyclopropanes (DACs) and donor–acceptor cyclobutanes (DABs) to afford medium-sized (hetero)cycles.1 Introduction2 (3+m) (m > 3) Annulations of Donor–Acceptor Cyclopropanes2.1 (3+4) Annulations2.2 (3+5) Annulations3 (4+m) (m > 2) Annulations of Donor–Acceptor Cyclobutanes4 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-09-28T11:06:45+01:00
DOI: 10.1055/a-2155-3615
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- Synthesis of Pyrido[2,3-d]pyrimidines Catalyzed by
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)/tert-Butyl Nitrite
(TBN)/O2-
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Authors: Cheng; Dongping, Xia, Hongshuang, Gu, Huafang, Wang, Yawei, Li, Jing-Hua, Xu, Xiaoliang
Abstract: Catalyzed by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)/tert-butyl nitrite (TBN)/O2, an efficient tandem oxidative reaction of uracils/thiouracil with 1,3-diarylpropenes is disclosed. It undergoes oxidative coupling, intramolecular cyclization, and dehydro-aromatization to provide multi-substituted pyrido[2,3-d]pyrimidines/thiopyrido[2,3-d]pyrimidines in moderate to excellent yields. It has the advantages of high atom economy, green terminal oxidant, and metal-free conditions.
Citation: Synthesis ; : -
PubDate: 2023-09-27T13:41:38+01:00
DOI: 10.1055/a-2156-7470
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- Recent Developments on the Synthesis of Sulfoxides via Sulfenate Anions
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Authors: Saito; Fumito
Abstract: Since the early 2000s, novel synthetic methods for the preparation of sulfoxides have emerged that involve sulfenate anions as sulfur nucleophiles. This short review showcases key advances in these sulfenate protocols, including catalytic enantioselective alkylation and arylation, and provides future directions for this research field.1 Introduction2 Precursors of Sulfenate Anions3 Organocatalytic Enantioselective Alkylation of Sulfenate Anions4 Palladium-Catalyzed Arylation of Sulfenate Anions5 Coupling of Sulfenate Anions with Hypervalent Iodine Reagents6 Conclusions and Outlook
Citation: Synthesis ; : -
PubDate: 2023-09-27T09:02:12+01:00
DOI: 10.1055/a-2155-3498
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- Oxidative Cyclization Reactions Catalyzed by Designed Transition-Metal
Complexes: A New Strategy for the Synthesis of Flavone, Quinolone, and
Benzofuran Derivatives-
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Authors: Singh; Apurva, Singh, Sain, Ghosh, Kaushik, Ahmed, Naseem
Abstract: An efficient and convenient synthetic protocol is reported for the synthesis of 2-phenyl-4H-chromen-4-one, 2-phenylquinolin-4(1H)-one, and 11H-benzofuro[3,2-b]chromen-11-one derivatives from 2′-hydroxychalcones, 2′-aminochalcones, and 3-hydroxyflavones, respectively, using transition-metal catalysts and TEMPO as an oxidizing agent. This catalytic heterocyclization approach involves in situ free-radical generation as phenoxyl radicals were detected by EPR spectroscopic study and H2O2 was formed. The present method has numerous advantages, such as high atom-economy, less hazardous synthesis, benign solvent and auxiliaries, easy handling, and broader substrate scope with good to excellent product yields.
Citation: Synthesis ; : -
PubDate: 2023-09-26T11:21:11+01:00
DOI: 10.1055/s-0042-1751489
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- Pd-Catalyzed Remote δ-C(sp2)–H Functionalization in Phenylalaninol:
Expanding the Library of Phenylalaninols-
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Authors: Singh; Prabhakar, Babu, Srinivasarao Arulananda
Abstract: We report the Pd(II)-catalyzed, picolinamide-directed δ-C(sp2)–H (ortho) functionalization of phenylalaninol scaffolds. Assembling of (ortho) δ-C–H arylated, alkylated, benzylated, alkenylated, brominated, and iodinated phenylalaninol scaffolds was accomplished. The δ-C(sp2)–H arylation reaction of phenylalaninol occurred under neat conditions. Hydrolysis of the picolinamide moiety and synthetic utility of the δ-C(sp2)–H arylated substrates were explored. We have also shown the preparation of some modified Matijin–Su (aurantiamide) derivatives using the bis δ-C–H (ortho) arylated phenylalaninol compounds obtained from the δ-C(sp2)–H arylation reaction (Matijin–Su is an anti-HBV agent possessing the phenylalaninol unit). Considering the importance of phenylalaninols, this work contributes to expanding the phenylalaninol library and demonstrates the substrate scope development in remote δ-C(sp2)–H functionalization reactions.
Citation: Synthesis ; : -
PubDate: 2023-09-25T07:52:51+01:00
DOI: 10.1055/a-2147-3518
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- Cobalt-Catalyzed Enantioselective Alkynylation of Oxabicyclic Alkenes
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Authors: Wei; Lin-Wen, Ma, Zhan-Cai, Wang, Zhao-Qing, Zhao, Yu, Huang, Yuan
Abstract: Efficient access to enantioenriched cyclic homopropargylic alcohols through an unprecedented cobalt-catalyzed asymmetric alkynylation of oxabicyclic alkenes has been developed. By using inexpensive cobalt salt/chiral bisphosphine ligand as the catalyst and easy-to-handle potassium alkynyltrifluoroborates as the nucleophile, synthetically valuable homopropargylic alcohols are obtained in moderate to good yields and high enantioselectivities.
Citation: Synthesis ; : -
PubDate: 2023-09-22T11:58:24+01:00
DOI: 10.1055/a-2152-0355
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- Synthesis and Immunological Evaluation of Escherichia coli O1-
Derived
Oligosaccharide–Protein Conjugates toward Avian Pathogenic Escherichia
coli O1 Vaccine Development-
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Authors: Seki; Katsunori, Makikawa, Takumi, Toshima, Kazunobu, Takahashi, Daisuke
Abstract: Avian pathogenic Escherichia coli O1 (APEC O1) is a pathogenic bacterium that causes significant economic losses in the poultry industry and raises concerns about zoonotic infections. The development of effective vaccines against APEC O1 is essential due to antibiotic resistance and the potential for severe symptoms in both chickens and humans. In this context, we have been focusing on the O1A, O1B, and O1C antigen structures derived from E. coli O1 lipopolysaccharide (LPS). In this study, the first synthesis of the pentasaccharide repeating units of the O1B and O1C antigens was successfully achieved. The synthesis and immunological evaluation of their conjugates with bovine serum albumin (BSA) were conducted. Only the O1A-pentasaccharide structure is a glycotope candidate for APEC O1. Keyhole limpet hemocyanin (KLH)–O1A-pentasaccharide conjugate was also synthesized, and its immunogenicity was evaluated by the ELISA assay. The efficient production of antibodies capable of binding to both APEC O1 LPS and the O1A-pentasaccharide structure was observed, indicating that O1A-pentasaccharide is a promising vaccine candidate against APEC O1.
Citation: Synthesis ; : -
PubDate: 2023-09-21T12:11:26+01:00
DOI: 10.1055/a-2152-0255
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- Rhodium-Catalyzed Regioselective Synthesis of N-Secondary Alkyl Indoles
via Intermolecular Cyclization of N-Nitrosoanilines and Unsymmetrical
Alkynes-
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Authors: Chang; Yiting, Hou, Tingting, Dong, Yi, Xu, Heng
Abstract: A Cp*Rh-catalyzed C–H functionalization/cyclization to afford 2,3-substituted N-secondary alkyl indole derivatives is described. This intermolecular cyclization of N-secondary nitrosoanilines and unsymmetrically substituted alkynes has good performances in yields, substrate scope, and regioselectivities.
Citation: Synthesis ; : -
PubDate: 2023-09-21T11:19:50+01:00
DOI: 10.1055/s-0041-1738453
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- The Electrocyclization of Heptatrienyl Anions
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Authors: Komijani; Samira, Orellana, Arturo
Abstract: The thermal electrocyclization of heptatrienyl anions is reviewed. We begin with a succinct background on the importance of cycloheptane rings in complex molecules and a brief survey of approaches to their synthesis. We also review the fundamental aspects of this electrocyclization manifold, relying on the Woodward–Hoffmann rules for pericyclic chemistry. Then we survey the literature, covering the burst of discovery in the late 1960s and early 1970s, and the more sporadic reports in from the 1990s to the present day.1 Introduction2 The Electrocyclization of Heptatrienyl Anions3 Discovery and Early Development (1964–1975)4 Recent Developments (1996–2023)5 Concluding Remarks
Citation: Synthesis ; : -
PubDate: 2023-09-20T12:24:04+01:00
DOI: 10.1055/s-0040-1720086
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- Application of the Heck Reaction for the Synthesis of C-Glycosyl Phenolic
Compounds-
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Authors: Tomé; Sara M., Soengas, Raquel G., Silva, Artur M. S.
Abstract: The potential of the Heck reaction for the C-glycosylation of phenolic compounds was explored. An efficient and general methodology for the synthesis of C-glycosylated phenolic compounds based on the Heck coupling of halogenated phenolic derivatives (chromones, 2-styrylchromones, and xanthones) and sugar alkenes was developed. The protocol was applied to the preparation of previously unreported C-glycosylated 2-styrylchromones and xanthones of potential biological relevance.
Citation: Synthesis ; : -
PubDate: 2023-09-19T12:42:37+01:00
DOI: 10.1055/a-2147-2788
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- Zinc-Mediated C–H Metalations in Modern Organic Synthesis
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Authors: Wanic; Daria K., Melvin, Rebecca, Barker, Graeme
Abstract: C–H Deprotometalations have long occupied a key role in modern organic synthesis in both the research laboratory and pharmaceutical and fine chemical manufacture, thanks to readily accessible reagents and well-established procedures. Typically, organolithiums are the reagent of choice thanks to high reactivity and ease of use but these are incompatible with base- and nucleophile-sensitive functional groups. In comparison, organozinc base complexes offer a milder approach to deprotonative C–H functionalisations, and compatibility with a wide range of functionalities which would be problematic when using the alternative organolithium or organomagnesium reagents has now been demonstrated. Here, we review the current state of the art in zinc-mediated C–H metalations at substituted arenes, heteroarenes, and Csp3–H sites.1 Introduction2 Csp2–H Functionalisation Using Zinc Bases2.1 Functionalised Arenes2.2 Heterocycles3 Csp3–H Functionalisation Using Zinc Bases3.1 Zinc Enolate Formation: Traditional Approach3.2 Zinc Enolate Formation via Zinc Bases3.3 Non-Enolic Csp3–H Zincations4 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-09-15T11:00:58+01:00
DOI: 10.1055/a-2155-3423
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- C-5 Epimerisation of d-Mannopyranosyl Fluorides: The Influence of Anomeric
Configuration on Radical Reactivity-
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Authors: See; Nicholas W., Pierens, Gregory K., Krenske, Elizabeth H., Ferro, Vito
Abstract: The fluorine-directing effect has so far been exploited to provide short and efficient synthetic routes to rare l-ido sugars. However, the importance of anomeric configuration to its success has remained experimentally unverified. We now report on the synthesis of α- and β-configured per-O-benzoylated mannopyranosyl fluorides and initially show that their reactivity towards photo-bromination is strongly dependent on the anomeric configuration. The stereochemical basis of the fluorine-directing effect is then validated by revealing the striking difference in stereoselectivity observed for the free-radical reductions of the isolated 5-C-bromo sugars. This work importantly provides a synthetic route to a donor-functionalised derivative of l-gulose and reveals new insights into the behaviour of glycosyl radicals.
Citation: Synthesis ; : -
PubDate: 2023-09-14T13:02:10+01:00
DOI: 10.1055/a-2149-4586
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- Divergent Synthesis and Biological Evaluation of 2,6-Disubstituted
Tetrahydropyran-Containing Natural Products: Parvistone E, Goniothalesdiol
A, 6-epi-Goniothalesdiol A, and 8-epi-9-Deoxygoniopypyrone-
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Authors: Zhao; Ziyang, Pan, Ruiying, Lv, Qingwei, Xie, Xinni, Liu, Jun, Du, Yuguo
Abstract: The concise and efficient synthesis of (+)-goniothalesdiol A and (–)-parvistone E (leiocarpin A), as well as the first total syntheses of (–)-6-epi-goniothalesdiol A and (–)-8-epi-9-deoxygoniopypyrone acetate, have been achieved in four or five longest linear steps based on the chiron approach. The potential biological activities of four 2,6-disubstituted tetrahydropyran-containing natural products were explored based on a panel of human cancer cell lines, BV-2 microglia and 3T3-L1 preadipocytes. Our results indicate that these four natural products display significant adipogenic activity in 3T3-L1 preadipocytes, but do not have clear effects on cancer cell proliferation or LPS stimulated microglia activation.
Citation: Synthesis ; : -
PubDate: 2023-09-14T12:09:27+01:00
DOI: 10.1055/a-2149-4214
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- Efficient Syntheses of (S)- and (R)-β-Proline
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Authors: Chandra; Shambhu Deo, Fung, Ethan W. F., Perrin, David M.
Abstract: A facile, efficient, and economical synthesis of both β-proline enantiomers starting from trans-4-hydroxy-l-proline is reported. Light-promoted radical Barton decarboxylation and nitrile introduction at C4 followed by hydrolysis gives the desired products in high optical purity. These routes should be of interest to those seeking economical access to β-proline for multiple applications.
Citation: Synthesis ; : -
PubDate: 2023-09-14T08:39:35+01:00
DOI: 10.1055/a-2145-5470
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- Synthesis of β-Hydroxyhydrophosphonic Acids from Inorganic Sodium
Hypophosphite-
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Authors: Qian; Dang-Wei, Yang, Jin, Wang, Gang-Wei, Yang, Shang-Dong
Abstract: An efficient approach to access β-hydroxyhydrophosphonic acid derivatives is reported by ring-opening reaction of readily available epoxides with green, inexpensive, and safe inorganic salt sodium hypophosphate as the phosphorus source in the presence of silver trifluoromethanesulfonate as the catalyst. The reaction is achieved under simple operation and exhibits excellent selectivity as well as good functional group compatibility.
Citation: Synthesis ; : -
PubDate: 2023-09-13T12:20:18+01:00
DOI: 10.1055/a-2133-1963
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- Carbon–Carbon Bond Forming Reactions in Diazines via
Transition-Metal-Catalyzed C–H Bond Activation-
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Authors: Gramage-Doria; Rafael, Bruneau, Christian
Abstract: An overview of the key achievements concerning C–C bond-forming processes with diazines (pyridazines, pyrimidines, and pyrazines) and benzodiazines (cinnolines, phthalazines, quinazolines, and quinoxalines) under transition-metal-catalyzed C–H activation is presented. The focus is on examples in which C–H functionalization takes place in the diazine or benzodiazine core because of the relevance of these compounds in material science and as active pharmaceutical ingredients. These metal-catalyzed protocols benefit from the biased reactivity of the C–H bonds targeted or from the presence of a rationally designed directing group proximate to the C–H bond to be functionalized. As such, innovative alkylations, alkenylations, alkynylations, arylations, and carboxylations are accomplished within such skeletons in a step- and atom-economy fashion.1 Introduction2 Transition-Metal-Catalyzed C–H Alkylation of Diazines3 Transition-Metal-Catalyzed C–H Alkynylation of Diazines4 Transition-Metal-Catalyzed C–H Alkenylation of Diazines5 Transition-Metal-Catalyzed C–H Arylation of Diazines6 Transition-Metal-Catalyzed C–H Carboxylation of Diazines7 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-09-12T11:59:39+01:00
DOI: 10.1055/a-2134-0307
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- Recent Progress on Copper-Catalyzed C–C Bond Formation via C(sp2)–H
Insertions Using Diazo and Related Compounds-
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Authors: Bera; Satabdi, Jana, Subhenira, Samanta, Rajarshi
Abstract: The site-selective insertion of metal carbenes via C(sp2)–H bond functionalization is an interesting topic within the synthetic chemistry community. In recent years, studies on the formation and applications of copper carbene intermediates have increased significantly due to their cost-effectiveness and versatile reactivities. Furthermore, copper-catalyzed transformations involving C(sp2)–H insertions using diazo and related compounds, along with asymmetric versions, have emerged as new tools for C–C bond formation. This short review summarizes selected recent advances in this field.1 Introduction2 Insertion of Copper Carbenes into Aryl C(sp2)–H Bonds of Arenes3 Copper Carbene Insertion into Aryl C(sp2)–H Bonds of Azaheteroarenes4 Copper Carbene Insertion into C(sp2)–H Bonds of Alkenes5 Conclusions and Perspectives
Citation: Synthesis ; : -
PubDate: 2023-09-08T12:32:31+01:00
DOI: 10.1055/a-2134-0352
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- A Concise and Flexible Synthesis of C2′-Sulfonylated Quinine
Derivatives-
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Authors: Gu; Cheng-Yu, Zhou, Jie, Tan, Dong-Xing, Han, Fu-She
Abstract: A concise and flexible procedure for the synthesis of structurally novel C2′-sulfonylated quinine derivatives is developed. Through careful optimization of the reaction conditions, most of the reactions can be performed in high yields at gram or several hundreds of milligram scale. Since cinchona-based derivatives are widely used in asymmetric catalysis, the synthetic route developed herein provides an efficient and practical pathway for the diverse synthesis of new cinchona derivatives as potential chiral ligands or multifunctional organocatalysts.
Citation: Synthesis ; : -
PubDate: 2023-09-07T11:49:13+01:00
DOI: 10.1055/a-2135-9037
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- One-Pot Synthesis of Quinoxaline N-Oxides via Radical-Mediated Cyclization
of Ketene N,S-Acetals-
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Authors: Kumar; Ganesh, Ray, Subhasish, Shukla, Gaurav, Singh, Maya Shankar
Abstract: A facile and efficient one-pot synthesis of bench-stable quinoxaline N-oxides has been realized using α-oxoketene N,S-acetals and tert-butyl nitrite (TBN) in open air via cascade annulation. The double functionalization of N,S-acetals proceeds through an unanticipated (Csp2)–H nitrosation by NO radical (generated in situ by TBN) and subsequent intramolecular N-arylation leading to quinoxaline, which undergoes oxidation to quinoxaline N-oxides harboring three variegated substituents on their framework. Notably, two new C–N bonds are formed with the same N-oxide nitrogen. This protocol features short reaction time, good functional group tolerance and mild conditions, and does not require the use of either catalyst or external additive.
Citation: Synthesis ; : -
PubDate: 2023-09-06T14:35:39+01:00
DOI: 10.1055/a-2128-5335
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- Synthetic Approaches to the 2019–2020 New Agrochemicals
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Authors: Jeanmart; Stephane, Edmunds, Andrew J. F., Lamberth, Clemens, Pouliot, Martin, Morris, James A.
Abstract: This review outlines the synthesis of the ten novel agrochemicals that received an International Standardization Organization (ISO) common name during 2019 and 2020. These agrochemicals will be used to control a wide range of weeds, insects and plant pathogens and their syntheses represent significant advances in the field of crop protection. The broad variety of different reactions, reagents and intermediates used to discover and produce this latest generation of agrochemicials is impressive.1 Introduction2 Fungicides and Virucides3 Herbicides4 Insecticides, Acaricides and Nematicides5 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-09-06T14:18:36+01:00
DOI: 10.1055/a-2142-8961
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- Advances in Nickel-Catalyzed O-Arylation of Aliphatic Alcohols and Phenols
with (Hetero)aryl Electrophiles-
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Authors: Morrison; Kathleen M., Stradiotto, Mark
Abstract: Transition-metal catalysis has been consequential in enabling carbon–heteroatom bond-forming reactions. Recent breakthroughs in Ni-catalyzed cross-couplings have offered competitive and, in some cases, superior reactivity to Pd- or Cu-based processes. Amidst the ongoing renaissance in this field, the Ni-catalyzed C–O cross-coupling of alcohols and (hetero)aryl (pseudo)halides has surfaced as an effective strategy for the synthesis of (hetero)aryl ethers. Methodologies to achieve such transformations tend to rely on one of three catalytic approaches: (i) thermal conditions often accompanied by ancillary ligand design tailored for Ni catalysis; (ii) the synergistic combination of photoredox and Ni catalysis; or (iii) electrochemically driven Ni catalysis. In some instances, these protocols have provided access to expanded C–O cross-coupling substrate scope, including the use of inexpensive and abundant electrophile coupling partners (e.g., (hetero)aryl chlorides). This Short Review aims to summarize recent progress in the development of Ni-catalyzed O-arylations of primary, secondary, and tertiary aliphatic alcohols, as well as phenols, with (hetero)aryl electrophiles.1 Introduction2 Thermally Promoted Ni C–O Cross-Coupling2.1 Primary and Secondary Aliphatic Alcohols2.2 Tertiary Aliphatic Alcohols2.3 Phenols3 Photochemically Promoted Ni C–O Cross-Coupling3.1 Primary and Secondary Aliphatic Alcohols3.2 Phenols4 Electrochemically Promoted Ni C–O Cross-Coupling4.1 Primary and Secondary Aliphatic Alcohols5 Conclusions and Outlook
Citation: Synthesis ; : -
PubDate: 2023-09-05T14:50:04+01:00
DOI: 10.1055/a-2134-0450
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- Electrochemical Dearomatizing Spirolactonization and Spiroetherification
of Naphthols and Phenols-
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Authors: Sarvi Beigbaghlou; Somayyeh, Yafele, Robert S., Kalek, Marcin
Abstract: An electrochemical oxidative ortho-dearomatization of naphthols and phenols with an intramolecular C–O bond formation has been developed. A careful optimization of the reaction parameters allowed for the application of free phenols as the starting materials, in contrast to the existing alternative procedures necessitating aryl methyl ether substrates. The reaction delivers an array of spirolactones and spiroethers in yields up to 97%, under simple experimental conditions: in a constant current mode, using an undivided cell, and without an inert atmosphere. The method avoids using catalysts or stoichiometric oxidants (e.g., hypervalent iodine reagents), generating hydrogen as the sole byproduct.
Citation: Synthesis ; : -
PubDate: 2023-09-05T14:04:09+01:00
DOI: 10.1055/a-2128-5408
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- Conformationally Restricted Carbocyclic γ-Amino Acids: Synthesis of
Diastereomeric 3-Amino-5-arylcyclopentane 1-Carboxylic Acids-
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Authors: Dumas; Adrien, Li, Da, Bonert, Steven, Aubeelucksing, Prashansing, Schaffner, Arnaud-Pierre, Hanessian, Stephen
Abstract: A Trost Pd-catalyzed [3+2] cycloaddition between a p-benzyloxy cinnamate bearing an Evans auxiliary and 1-trimethylsilyl-2-acetoxymethylpropene is disclosed leading to, after functional group manipulation, previously unreported diastereoisomeric 3-amino-5-arylcyclopentane 1-carboxylic acids via the corresponding 3-hydroxy and 3-azido precursors. The availability of these conformationally restricted cyclic amino acids may find utility in the context of CNS-active compounds related to GABA, or as peripheral units of bioactive pharmaceuticals. An expedient alternative 4-step synthesis of 3S-amino-5S-p-hydroxyphenyl-1S-cyclopentane carboxylic acid methyl ester was achieved starting with the (–)-Vince lactam and utilizing a regio- and diastereoselective Pd-catalyzed hydroarylation reaction.
Citation: Synthesis ; : -
PubDate: 2023-09-04T11:43:28+01:00
DOI: 10.1055/s-0042-1751484
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- Exploratory Process Development of a Pulmonary Arterial Hypertension
Clinical Compound via a Late-Stage Pd-Catalyzed Buchwald–Hartwig C–N
Coupling-
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Authors: Algera; Russell F., Davidson, Andrew, Herbert, David K., Lian, Yajing, Liu, Fangfang, Liu, Yiyang, Nematalla, Asaad, Piper, Jared L., Magano, Javier, Monfette, Sebastien, Nguyen, Bao, Raggon, Jeffrey W., Rainville, Joseph P., Rane, Anil, Tao, Yong, Wang, Ke, Yayla, Hatice G.
Abstract: The development of a robust process for a Pd-catalyzed Buchwald–Hartwig C–N coupling reaction to manufacture PF-06842874, a clinical candidate for the treatment of pulmonary arterial hypertension, on kilogram scale is reported. The variability in reaction kinetics initially encountered was resolved via the use of sodium tert-butoxide as a homogeneous base and a careful selection of precatalyst by examination of the catalyst activation mechanism. Extraction with aqueous acid followed by careful pH adjustment allowed us to isolate the product with excellent purge of impurities. The process was successfully implemented in up to 18 kg demonstration.
Citation: Synthesis ; : -
PubDate: 2023-09-04T11:27:09+01:00
DOI: 10.1055/s-0040-1720087
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- Decoration on Cubane with an Awareness of Chirality: Development of
Substituted Cubane Syntheses-
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Authors: Takebe; Hiyori, Matsubara, Seijiro
Abstract: Nearly 60 years have passed since Professor Eaton’s practical synthesis of cubane, and research using it as a unique molecular scaffold has since gained momentum. Since the early synthesis of polynitrocubane, it has been shown that up to eight substituents can be covalently assembled into a confined space. The arrangement of substituents on cubane has paved the way for the creation of unique asymmetric molecules. To put it another way, chirality is manifested by selectively introducing three or more diverse types of substituents at specific sites. Recently, there has also been a report on the synthesis of perfluorocubane, a molecule with intriguing electronic properties.1 Introduction2 General Information3 Functionalization of Cubane4 Preparation of Polysubstituted Cubanes5 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-08-31T11:06:29+01:00
DOI: 10.1055/a-2124-3823
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- Site-Selective Lewis Acid Mediated Transformation of Pseudo Glycals to
1-Deoxy-2-thioaryl/alkyl Glycosides-
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Authors: Tiwari; Bindu, Sharma, Manish K., Pandey, Ram P., Hussain, Nazar
Abstract: A site-selective Lewis acid mediated transformation of pseudoglycals with various thiols for the synthesis of C-2 thioaryl glycosides was developed. The substrate scope of the reaction was explored with various thiols having various functional groups on aromatic rings as well as with pseudoglycals obtained from different sugars. The compatibility and survival of various protecting groups on pseudoglycals and substituted thiols show tolerance under the reaction conditions. Finally, the potential synthetic utility of the synthesized compounds was demonstrated and also the late-stage modifications of various drugs and pharmaceuticals were also explored.
Citation: Synthesis ; : -
PubDate: 2023-08-30T12:00:01+01:00
DOI: 10.1055/a-2126-0815
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- Platinum(II) Complexes with Phenylpyridine, Benzo[h]quinoline, and NHC
Ligands: Exploration of Ligand Effects on Photophysical Properties-
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Authors: Pinter; Piermaria, Soellner, Johannes, Strassner, Thomas
Abstract: Platinum(II) complexes with one cyclometalated phenylpyridine or benzo[h]quinoline (C^N) ligand and an N-heterocyclic carbene (NHC) ligand are a robust and readily available class of sky-blue to green phosphorescent triplet emitters. They can be used as a benchmark system to investigate the influence of different ligands on the emissive properties of these [Pt(C^N)(NHC)I] complexes. This new class of compounds was fully characterized by standard techniques. Additionally a solid-state structure could be obtained. Photoluminescence measurements at room temperature revealed the strong emissive behavior of these compounds with quantum yields of up to 80%. The effect of electron-withdrawing and -donating groups on the photophysical properties was examined and rationalized by density functional theory calculations (PBE0/6-311G(d)).
Citation: Synthesis ; : -
PubDate: 2023-08-28T14:23:25+01:00
DOI: 10.1055/s-0042-1751482
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- Synthesis and Cytotoxic Evaluation of
2-Aryl-7,8-dihydroquinolin-6(5H)-ones-
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Authors: Bautista; Diego Díaz, Blé González, Ever A., Chávez Santos, Rosa María, Ramírez Apán, María Teresa, Vilchis Reyes, Miguel A., Martínez, Roberto
Abstract: Herein we present a facile four-step synthetic method for the synthesis of novel 2-aryl-substituted 7,8-dihydroquinolin-6(5H)-ones as cytotoxic agents. The key step was the use of Mannich salts derived from acetophenones as a Michael acceptor in the reaction with cyclohexane-1,4-dione monoethylene acetal to give 1,5-dicarbonyl compounds that were treated with ammonium acetate to give the 7,8-dihydroquinolin-6(5H)-ones. The cytotoxic activity of the synthesized compounds was evaluated against seven cell lines. The observed data showed good selectivity for chronic myeloid leukemia line K-562. The synthetic route was simple and applicable to various functional group containing substrates. These types of compounds may be utilized as lead compounds in cancer research and drug discovery.
Citation: Synthesis ; : -
PubDate: 2023-08-28T13:11:41+01:00
DOI: 10.1055/s-0041-1738451
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- Studies on Selective Metalation and Cross-Coupling Reactions of Oxazoles
-
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Authors: Wagner; Raphael, Wollnitzke, Philipp, Essig, Sebastian, Gölz, Jan P., Menche, Dirk
Abstract: A general study on selective functionalization of unsubstituted oxazole is reported. Specific halogenation at C2 and C5 was enabled by a sequential deprotonation strategy that was based on the different pK a values of these positions, while a halide at C4 may be introduced by an optimized halogen dance reaction. Efficient protocols for subsequent sp2–sp2 and sp2–sp3 cross-coupling reactions of the derived oxazolyl halides were then established. This modular approach was applied in the total synthesis of ajudazol A and a selected analogue, demonstrating the general feasibility of these conditions in a complex setting.
Citation: Synthesis ; : -
PubDate: 2023-08-24T15:17:31+01:00
DOI: 10.1055/a-2126-0720
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- Palladium-Loading Ceramic Catalytic Membrane Reactors for
Mizoroki–Heck Reaction-
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Authors: Zhang; Fei, Zhou, Yong, Wang, Shuangqiang, Zhao, Yao, Wu, Xiaojin, Chen, Rizhi
Abstract: The general and efficient palladium-loading ceramic catalytic membrane reactor has been first reported to apply in the Mizoroki–Heck reaction. The as-fabricated catalytic membrane Pd-KH792-CM has shown high activity and selectivity in the flow-through Mizoroki–Heck reactions. The consistently high activity of the catalytic membrane in the five cycles has also proved its good stability and recyclability. Synthesis of drug molecules has further demonstrated that the catalytic membrane protocol is a powerful and comprehensive alternative to the traditional Mizoroki–Heck cross-coupling.
Citation: Synthesis ; : -
PubDate: 2023-08-22T13:02:13+01:00
DOI: 10.1055/a-2119-5236
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- Photocatalyst-Free Visible-Light-Promoted C–H Selenylation of
Pyrazolo[1,5-a]pyrimidines-
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Authors: Sikdar; Papiya, Choudhuri, Tathagata, Paul, Suvam, Das, Sourav, Kumar, Anil, Bagdi, Avik Kumar
Abstract: A new method has been developed for the C–H selenylation of pyrazolo[1,5-a]pyrimidine derivatives under the irradiation of visible light. This photocatalyst-free strategy is applicable to a wide range of pyrazolo[1,5-a]pyrimidines with broad functionalities. The salient features of the method are mild reaction conditions, use of bench-stable oxidant, high regioselectivity, and scalability.
Citation: Synthesis ; : -
PubDate: 2023-08-21T08:59:24+01:00
DOI: 10.1055/a-2124-5485
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- Improved Syntheses of an Arseno-Fatty Acid (As-FA 362) and an
Arseno-Hydrocarbon (As-HC 444)-
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Authors: Chacon-Teran; Miguel A., Bhattacharjee, Shubhra, Bailoo, Jeremy D., Deonarine, Amrika, Findlater, Michael
Abstract: Robust and reliable synthetic methods have been developed for the preparation of an arseno-fatty acid (As-FA362) and an arseno-hydrocarbon (As-HC444). An improved route to access the starting materials necessary for the new synthetic routes is also disclosed. With these improvements, an increased accessibility to arsenic-containing compounds is anticipated, which may be deployed as standards required for the development of quantitative methods in biological matrices. For the first time, stability data for these compounds are reported. With these results in hand, data on the elimination profile, bioaccumulation potential and patho-behavioral and physiological consequences of these organoarsenicals are planned.
Citation: Synthesis ; : -
PubDate: 2023-08-17T13:02:26+01:00
DOI: 10.1055/a-2122-4287
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- Efficient Synthesis of Diethyl, Dialkyl
α-Hydroxy-propylenebisphosphonates and Related
5-Phosphonoyl-1,2-oxaphospholane 2-Oxides-
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Authors: Varga; Petra Regina, Belovics, Alexandra, Karaghiosoff, Konstantin, Szabó, Rita, Bősze, Szilvia, Drahos, László, Keglevich, György
Abstract: A series of new dialkyl α-diethylphosphonoylethyl-α-hydroxy-ethylphosphonates were prepared using the Pudovik reaction of the corresponding γ-oxophosphonate with dialkyl phosphites performed on the surface of Al2O3/KF. The adducts revealed unexpected reactivity in the attempted O-acylation reaction, and provided the corresponding 5-phosphonoyl-1,2-oxaphospholane 2-oxides. On treatment with Cs2CO3, instead of the expected rearrangement a cyclization reaction leading to the same ring products took place. Three of the phosphonoylethyl-α hydroxy-ethylphosphonates, along with two phosphonoylmethyl analogues revealed significant and selective anticancer effect on A431 cells, and occasionally, on PC-3 and MDA-MB 231 cells.
Citation: Synthesis ; : -
PubDate: 2023-08-17T12:45:07+01:00
DOI: 10.1055/a-2122-4178
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- Access to Symmetrical and Unsymmetrical Cyclobutanes via Template-Directed
[2+2]-Photodimerization Reactions of Cinnamic Acids-
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Authors: Yagci; Bilge Banu, Munir, Badar, Zorlu, Yunus, Türkmen, Yunus Emre
Abstract: In this work, we have developed a general and broadly applicable template-directed photochemical [2+2]-cycloaddition reaction which provides access to a wide range of symmetrical and unsymmetrical cyclobutane products. The use of 1,8-dihydroxynaphthalene as a covalent template paved the way for successful and highly selective photochemical homodimerization and heterodimerization reactions in the solid state between cinnamic acid derivatives. Notably, the method works equally well with aryl- and heteroaryl-containing substrates leading to the formation of β-truxinic acid analogues as single diastereomers and in high yields (up to 99%).
Citation: Synthesis ; : -
PubDate: 2023-08-16T13:06:16+01:00
DOI: 10.1055/a-2126-3774
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- Direct Organocatalytic Asymmetric para C–H Aminoalkylation of Aniline
Derivatives Affording Diarylmethylamines-
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Authors: Wang; Cheng-Long, Li, Yong-Ling, Wang, Le, Wang, Xun-Hui, Zhou, Jia, Bai, He-Yuan, Ding, Tong-Mei, Sun, Zhen-Liang
Abstract: An efficient method to directly catalyze asymmetric para C–H aminoalkylation of aniline derivatives to prepare chiral diarylmethylamine system was developed. Aniline derivatives underwent an enantioselective aminoalkylation in the presence of chiral phosphoric acid, affording a series of optically active diarylmethylamine products in good yields and enantioselectivities (73% yield, 91% ee). Furthermore, this method could be used to prepare the key intermediate of chiral drug levocetirizine.
Citation: Synthesis ; : -
PubDate: 2023-08-16T10:36:38+01:00
DOI: 10.1055/a-2122-3731
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- Palladium-Catalyzed Homo-Dimerization of Terminal Alkynes
-
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Authors: Chen; Xia, Guo, Hong-Yu, Zhou, Xiao-Yu, Bao, Ming
Abstract: The palladium-catalyzed homo-dimerization of terminal alkynes is a powerful and atom-economic method for the preparation of highly unsaturated four-carbon skeletons, which are key structural units found in natural and/or biologically active products and materials. However, during the homo-dimerization of terminal alkynes, a major issue is control of the chemo-, regio-, and stereoselectivity. Thus, over the past few decades, various strategies and methods have been developed that employ palladium catalytic systems for such homo-dimerizations. In this Short Review, we highlight important methods for the selective synthesis of these valuable four-carbon compounds, including conjugated 1,3-enynes, 1,3-diynes, and 1,3-dienes.1 Introduction2 Redox-Neutral Homo-Dimerization of Terminal Alkynes for the Synthesis of 1,3-Enynes2.1 Head-to-Head Dimerization2.2 Head-to-Tail Dimerization3 Oxidative Homo-Dimerization of Terminal Alkynes for the Synthesis of 1,3-Diynes3.1 Unsupported Palladium Catalysts3.1.1 Choice of Oxidant3.1.2 Choice of Ligand3.1.3 Choice of Solvent3.2 Supported Palladium Catalysts4 Reductive Homo-Dimerization of Terminal Alkynes for the Synthesis of 1,3-Dienes5 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-08-16T10:11:37+01:00
DOI: 10.1055/a-2124-3903
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- Continuous-Flow Regioselective Reductive Alkylation of Oxindole with
Alcohols and Aldehydes in a Fast and Economical Manner-
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Authors: Mándoki; András, Orsy, György, Pászti, Zoltán, Porcs-Makkay, Márta, Bogdán, Dóra, Simig, Gyula, Mándity, István, Volk, Balázs
Abstract: Oxindole is a widely used scaffold in drug discovery, which can be found in several marketed drugs, among them sunitinib and ziprasidone. Thus, the derivatization of oxindole is of considerable current interest. The extreme reaction conditions (high temperature, high pressure) described in the literature for the batchwise regioselective multistep 3-alkylation of oxindole with alcohols in the presence of Raney nickel motivated us to develop a robust, time- and cost-efficient continuous-flow variant for this reaction. In addition, the continuous-flow technology was also extended to the reductive 3-alkylation of oxindole with aldehydes. The elaborated methodology allows the safe use of Raney nickel, an inexpensive and widely applied, albeit pyrophoric catalyst. Under the optimized reaction conditions, 10 oxindole derivatives were synthesized ranging from simple 3-alkyl to 3-aralkyl derivatives including two (trifluoromethyl)benzyl congeners. The technology is considerably robust and the catalyst showed a long-term usability. The model reaction between oxindole and acetaldehyde could be run for 16 hours uninterruptedly, rendering possible the efficient ethylation of about 20 g of oxindole utilizing only approximately 800 mg of Raney nickel.
Citation: Synthesis ; : -
PubDate: 2023-08-15T13:10:53+01:00
DOI: 10.1055/a-2122-4080
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- C–H Functionalization of Arenes via NHC-Supported Ni/Al Bimetallic
Catalysis-
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Authors: Jiang; Binyang, Shi, Shi-Liang
Abstract: Despite the C–H functionalization of arenes offering an efficient synthetic route towards functionalized aromatic compounds with high atom- and step-economy, the low reactivity of the C–H bond makes this transformation rather challenging. Compared with mono-metal catalysis, the introduction of bimetallic catalysis would greatly enhance the reactivity and selectivity of this transformation. In this review, we highlight recent progress in the C–H functionalization of arenes via NHC-Ni/Al catalysis. The added aluminum as a co-catalyst would activate arene through Lewis acid-base interaction, and regioselectivity could be controlled through the synergism of NHC-Ni and Al. This strategy could be also applied in enantioselective C–H alkylation with well-designed chiral NHC ligands.1 Introduction2 C–H Addition to Alkynes via C–H Activation3 C–H Alkylation via Ni/Al Bimetallic Catalysis3.1 Racemic Hydroarylation with Alkenes3.2 Asymmetric Hydroarylation with Alkenes4 Conclusion and Outlook
Citation: Synthesis ; : -
PubDate: 2023-08-15T11:35:23+01:00
DOI: 10.1055/a-2114-5508
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- A Photoinduced Palladium-Catalyzed Cascade Reaction for the Synthesis of
Chiral Piperidines with Chiral Amino Acid Derivatives and 1,3-Dienes-
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Authors: Song; Shun, Yin, Yi-Zhuo, Han, Zhi-Yong
Abstract: A photoinduced palladium-catalyzed cascade reaction involving remote C(sp3)–H functionalization and intramolecular Tsuji–Trost annulation is developed. The reaction is proposed to proceed through a sequence involving the amidyl radical generation, 1,5-HAT-mediated alkyl radical formation, and subsequent difunctionalization of 1,3-dienes. Without the use of exogeneous photosensitizers and external oxidants, the reaction provided an efficient approach to multi-substituted chiral piperidines in high yields, employing readily available chiral amino acid derivatives and 1,3-dienes as the substrates. In most cases, the syn/anti ratio of the product could be further improved by treatment with catalytic amount of iron salt.
Citation: Synthesis ; : -
PubDate: 2023-08-14T15:07:04+01:00
DOI: 10.1055/a-2122-1573
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- Construction of an Epoxy-lactone Moiety on the C/D Ring of Highly
Oxygenated Triterpenes through a Modified SeO2-Promoted Oxidative
Cyclization-
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Authors: Chen; Yang, Li, Qiao-Yue, Xie, Xiao-Yan, Wang, Wei, Li, Dashan, Wang, Wen-Jing, Shao, Li-Dong
Abstract: We present herein a synthetic endeavor to prepare the epoxy-lactone moiety commonly present in the C/D ring of highly oxygenated triterpenes. Two strategies are applied starting from ursolic acid: (i) Br+-promoted cyclization–isomerization for late-stage epoxidation, and (ii) one-step SeO2-promoted oxidative cyclization. Additionally, the desired epoxy-lactone moiety can be readily prepared on gram scale in one step by using the modified SeO2/TBHP/AcOH oxidative system.
Citation: Synthesis ; : -
PubDate: 2023-08-14T12:47:25+01:00
DOI: 10.1055/a-2122-4021
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- Sustainable Ru(II)-Catalyzed ortho-C(sp2)–H Hydroxyalkylation of
Phthalazinones Using Ethyl Glyoxalate: Access to α,α′-Arylcarboxy
sec-Alcohols-
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Authors: Ramkumar; Alagumalai, Gandhi, Thirumanavelan
Pages:
Citation: Synthesis ; : -
PubDate: 2023-08-07T09:48:26+01:00
DOI: 10.1055/a-2114-5426
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- Molybdenum-Mediated One-Pot Synthesis of 2-Hydroxypyrimidines from
Isoxazoles-
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Authors: Rochelle; Servane, Beaumont, Stéphane
Abstract: A one-pot procedure towards substituted 2-hydroxypyrimidines from commercially available isoxazoles is reported. The process involves cleavage of the isoxazole N–O bond mediated by Mo2(OAc)4, then in situ hydrolysis of the resulting β-amino enone to the reactive 1,3-dicarbonylated intermediate, followed by hydroxypyrimidine formation in the presence of urea. Moderate to excellent yields are obtained, leading to functionalized hydroxypyrimidines. By using readily available isoxazoles, a wide range of new diverse polysubstituted hydroxypyrimidines may be prepared by this method.
Citation: Synthesis ; : -
PubDate: 2023-08-01T10:27:45+01:00
DOI: 10.1055/a-2107-4492
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- Titanium-Catalyzed Intermolecular Hydroaminoalkylation of Terminal Alkynes
-
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Authors: Thye; Hermann, Fornfeist, Felix, Geik, Dennis, Schlüschen, Levi L., Schmidtmann, Marc, Doye, Sven
Abstract: Terminal alkynes undergo intermolecular hydroaminoalkylation reactions with secondary amines in the presence of titanium catalysts and depending on the catalyst and the structure of the substrates, allylic amines and/or imines are formed as products in moderate yields. In addition, the desired allylamines can also be obtained from a convenient reaction sequence consisting of an initial hydroaminoalkylation of trimethylsilyl-protected alkynes and a subsequent protodesilylation that selectively delivers γ-unsubstituted allylamines.
Citation: Synthesis ; : -
PubDate: 2023-07-27T14:27:13+01:00
DOI: 10.1055/a-2111-9910
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- Activation of Diazo Compounds by Fluorinated Triarylborane Catalysts
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Authors: Pramanik; Milan, Melen, Rebecca L.
Abstract: The diverse applicability of diazo compounds as versatile reagents has enlarged the chemical toolbox in organic synthesis. Over the past few decades, transition-metal-catalyzed diazo compound activation has ignited the classical synthetic methodology via utilizing highly reactive metal carbenoid species. Many reviews have also appeared in the literature that show the advantages and disadvantages of metal-catalyzed activation of diazo compounds. Recently, tris(pentafluorophenyl)borane-mediated diazo activation reactions has remodeled this research area due to the potential for mild, environmentally friendly, metal-free, nontoxic reaction conditions, and the diverse reactivity patterns of boranes towards diazo compounds. In this review, we discuss the reactivity of the boron–diazo precursor adducts with compounds using catalytic and stoichiometric halogenated triarylboranes and, the mechanism of N2 release from the diazo reagent. This generates the reactive carbene species as a key intermediate which can further be exploited for O–H, N–H, S–H, and C–H insertions, azide insertion, carbonate transfer, C–C and C=C bond forming reactions, [2+2] or [2+4] cascade cyclization reactions, annulation reactions, etc.1 Introduction2 Diazo Activation Using Stoichiometric Boranes3 Diazo Activation Using Catalytic B(C6F5)3 4 B(C6F5)3-Catalyzed Diazo Activation Reactions5 Conclusions
Citation: Synthesis ; : -
PubDate: 2023-07-26T13:16:17+01:00
DOI: 10.1055/a-2118-3046
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- Synthetic Strategies for Accessing Dibenzophosphole Scaffolds
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Authors: Hattori; Hiroyuki, Ishida, Kento, Sakai, Norio
Abstract: Dibenzophospholes, phosphorus-containing π-conjugated cyclic compounds, have attracted considerable attention because of their potential applications in various functional materials such as those required for organic electroluminescent devices. Moreover, their synthetic methods have been widely developed. This review summarizes the construction strategies of dibenzophosphole scaffolds, including those developed recently.1 Introduction2 Construction of a Phosphole Skeleton Using Aryl Compounds2.1 [4+1] Cyclization between Biaryl Derivatives and P1 Units2.2 Intramolecular P–C Bond Formation of Biarylphosphines2.3 Intramolecular C–C Bond Formation of Diarylphosphines2.4 [3+2] Cyclization between Arylphosphines and Arenes3 Fused-Benzene Ring Formation4 Successive Phosphole Skeleton and Fused-Benzene Ring Formation5 Conclusions
Citation: Synthesis ; : -
PubDate: 2023-07-25T15:11:04+01:00
DOI: 10.1055/a-2109-0003
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- Ni- and Pd-Catalyzed Enantioselective 1,2-Dicarbofunctionalization of
Alkenes-
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Authors: Kang; Taeho, Apolinar, Omar, Engle, Keary M.
Abstract: Catalytic enantioselective 1,2-dicarbofunctionalization (1,2-DCF) of alkenes is a powerful transformation of growing importance in organic synthesis for constructing chiral building blocks, bioactive molecules, and agrochemicals. Both in a two- and three-component context, this family of reactions generates densely functionalized, structurally complex products in a single step. Across several distinct mechanistic pathways at play in these transformations with nickel or palladium catalysts, stereocontrol can be obtained through tailored chiral ligands. In this Review we discuss the various strategies, mechanisms, and catalysts that have been applied to achieve enantioinduction in alkene 1,2-DCF.1 Introduction2 Two-Component Enantioselective 1,2-DCF via Migratory Insertion3 Two-Component Enantioselective 1,2-DCF via Radical Capture4 Three-Component Enantioselective 1,2-DCF via Radical Capture5 Three-Component Enantioselective 1,2-DCF via Migratory Insertion6 Miscellaneous Mechanisms7 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-07-25T13:07:56+01:00
DOI: 10.1055/a-2108-9549
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- C–H Bond Silylation of Heteroarenes
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Authors: Khatua; Hillol, Das, Subrata, Patra, Sima, Chattopadhyay, Buddhadeb
Abstract: Organosilicon compounds are highly important molecular scaffolds with versatile synthetic utility, and are used in a range of transformations. Such organosilicon compounds are employed in a wide range of research areas, including medicinal chemistry, drug discovery, pharmaceuticals, agrochemicals, fine chemicals, etc. Moreover, they are commonly encountered in a number of commercial products. However, the preparation of organosilicon compounds by means of traditional methods significantly limit their wider applications. Recently, several new concepts and powerful methods have been developed in order to prepare organosilicon compounds via transition-metal catalysis or without metal catalysis. While many procedures have been reported for the silylation of aromatic systems, methods for the silylation of heteroarenes are scarce. Nevertheless several excellent and robust strategies for heteroarene silylation have been discovered. In this short review, we summarize the different methods, mechanisms and catalyst development for the regioselective silylation of heteroarenes.1 Introduction2 Silylation of C–H Bonds through Organometallic Intermediates2.1 Intermolecular C–H Bond Silylation Assisted by Directing Groups2.2 Undirected Intermolecular C–H Bond Silylation2.3 Intramolecular C–H Bond Silylation via a Tethered Silyl Unit3 C–H Bond Silylation with Silicon Electrophiles4 C–H Bond Silylation with Silicon Nucleophiles5 C–H Bond Silylation with Silyl Radicals6 Other Approaches6.1 Alkali-Metal-Catalyzed C–H Bond Silylation6.2 Magnesium-Promoted Reductive C–H Bond Silylation7 Conclusions and Outlook
Citation: Synthesis ; : -
PubDate: 2023-07-24T10:47:48+01:00
DOI: 10.1055/a-2110-4581
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- Developing Organometallic Nucleophilic Reagents Via Photoredox Catalysis
-
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Authors: Gualandi; Andrea, Calogero, Francesco, Pinosa, Emanuele, Corbisiero, Dario, Cozzi, Pier Giorgio
Abstract: The addition of organometallic reagents to the carbonyl group represents a key transformation, both in academia and industry. Most of these transformations rely on a mechanism in which accessible and reactive halides are transformed into the corresponding nucleophilic organometallic reactive compounds through a redox mechanism, using a metal (Cr, Mg, In, etc.) in low oxidation state, by electron transfer. With the advent of photoredox catalysis, the formation of radicals, through oxidation or reduction of suitable and tailored organic precursors, was merged with transition metal catalysis. By radical-to-polar crossover (RPCO), a radical metal is combined with an organic radical to produce, via radical-radical trapping, a polar nucleophilic organometallic reagent. Using dual photoredox catalysis (metallaphotoredox catalysis), a reactive organometallic reagent can be prepared, avoiding the use of metals in low oxidation state. Herein, in addition to the description of the results obtained by our group and the contributions of others on the connection between carbonyl addition and radical-based photochemistry, we provide core guidance for further synthetic developments. We anticipate that extending the photoredox dual strategy beyond the Barbier reactions described here, taming less-activated carbonyls, studying other important electrophiles, will soon realize important breakthroughs.1 Introduction2 Photoredox Catalysis: A Survival Guide for the ‘Photo-Curious’3 Chromium Nucleophilic Organometallic Reagents3.1 Allylation of Aldehydes3.2 Allylation of Aldehydes via Dienes3.3 Propargylation of Aldehydes via 1,3-Enynes3.4 Alkenylation of Aldehydes3.5 Alkylation of Aldehydes3.6 Enantioselective Chromium-Mediated Photoredox Reactions4 Titanium Nucleophilic Organometallic Reagents4.1 Allylation Reactions4.2 Propargylation Reactions4.3 Allylation Reactions via Dienes4.4 Benzylation Reactions4.5 Alkylation Reactions5. Cobalt Nucleophilic Organometallic Reagents5.1 Allylation Reactions6 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-07-17T09:36:00+01:00
DOI: 10.1055/a-2107-4416
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- Gold(I)-Catalyzed Dearomatization–Allenene Reaction for the Construction
of Polycycles with Excellent Diastereoselectivity-
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Authors: Semleit; Nina, Haberhauer, Gebhard
Abstract: The synthesis of complex polycycles starting from simple building blocks in just a few reaction steps is usually very challenging. Herein, we present the gold(I)-catalyzed synthesis of various polycycles via the dearomatization–allenene reaction of aryl propargyl ethers with different nucleophiles. Depending on the starting material, polycycles can be isolated in yields up to 94% and with an enantiomeric excess of 95%. Quantum chemical calculations show that for all starting materials a Claisen rearrangement to the allenene occurs in the first reaction sequence. The subsequent cyclization and reaction with a nucleophile leads to various polycycles with the formation of up to six new C–C bonds in only one reaction step. All reactions proceed with excellent diastereoselectivity, with an α-quaternary carbonyl carbon present in the products.
Citation: Synthesis ; : -
PubDate: 2023-07-10T11:45:02+01:00
DOI: 10.1055/a-2109-1642
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- Synthesis of (2-Aminopyrimidin-4-yl)(pyridin-4-yl)methanone and
Derivatives-
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Authors: Giraud; Francis, Josselin, Béatrice, Ruchaud, Sandrine, Anizon, Fabrice, Moreau, Pascale
Abstract: Pyrido[3,4-g]quinazoline was previously identified as a relevant scaffold for protein kinase inhibition. In order to assess if the planarity of this heterocyclic system was essential to the protein kinase inhibitory potency observed in this series, new compounds were synthesized and evaluated, in which the central cycle was opened to provide (pyridin-4-yl)(pyrimidin-4-yl)methane derivatives, which were prepared from the corresponding ketone precursor. After preparing (2-aminopyrimidin-4-yl)(pyridin-4-yl)methanone, derivatives were synthesized and evaluated toward a panel of protein kinases. The results demonstrated that the planar pyrido[3,4-g]quinazoline tricyclic system was mandatory to maintain the protein kinase inhibitory potency in this series.
Citation: Synthesis ; : -
PubDate: 2023-07-10T09:43:40+01:00
DOI: 10.1055/a-2107-4571
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- Palladium-Catalyzed Oxidative Cycloaddition of
Quinazoline-2,4(1H,3H)-diones and Diarylalkynes via C–H/N–H Activation
-
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Authors: Komolova; Darya D., Pronina, Yulia A., Lozovskiy, Stanislav V., Selivanov, Stanislav I., Ponyaev, Alexander I., Filatov, Alexander S., Boitsov, Vitali M., Stepakov, Alexander V.
Abstract: The oxidative cycloaddition of 3-subsituted quinazoline-2,4(1H,3H)-diones and alkynes has been developed. The reaction is Pd(II)-catalyzed and successfully occurs in the presence of Ag(I) oxidants. This transformation is assumed to proceed by N–H palladation of the quinazoline-2,4(1H,3H)-dione followed by ortho-C–H activation. Using this methodology, a series of 5,6,7,8-tetraaryl-1H-azepino[3,2,1-ij]quinazoline-1,3(2H)-diones were obtained in moderate to good yields. The resulting tricyclic heterocycles can be converted by alkaline hydrolysis into 1H-benzo[b]azepine-9-carboxamide derivatives. DFT calculations have been carried out to shed light on the reaction mechanism.
Citation: Synthesis ; : -
PubDate: 2023-07-04T11:21:46+01:00
DOI: 10.1055/a-2105-2850
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- One-Pot Telescopic Approach to Synthesize Disubstituted Benzimidazoles
in Deep Eutectic Solvent-
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Authors: Das; Soumyadip, Chanda, Kaushik
Abstract: An ongoing challenge in the pharmaceutical sector is the need to find and implement novel synthetic approaches because traditional methods sometimes violate the principles of green chemistry. While benzimidazoles are of great importance as building blocks for the creation of molecules having pharmacological activity, the development of methods for their sustainable synthesis has been a challenge for organic synthesis. Herein, we have carried out a one-pot telescopic approach to the synthesis of disubstituted benzimidazole derivatives in a deep eutectic solvent (DES) medium to investigate an alternate synthetic technique. Starting with methyl 4-fluoro-3-nitrobenzoate, SNAr reaction, reduction, and cyclization were performed with choline chloride/glycerol/H2O as DES medium, which gave the best performance out of the five DESs examined. We report the synthesis of disubstituted benzimidazoles via one-pot telescopic approach.
Citation: Synthesis ; : -
PubDate: 2023-07-03T14:07:54+01:00
DOI: 10.1055/a-2102-1192
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- An Alternative Formal Synthesis of (S)-(+)-Vigabatrin
-
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Authors: Chaskar; Sudhir P., Honparkhe, Ramchandra, Aghao, Arvind K., Thorat, Rakesh G., Pramanik, Chinmoy
Abstract: An improved synthesis of chirally pure advanced pyrrolidone intermediate of the (S)-(+)-vigabatrin, an antiseizure active pharmaceutical ingredient (API) is reported. The synthesis is developed using commercially available, cheaper amino acid (R)-methionine. Meldrum’s acid served as a two-carbon homologation unit to access the pyrrolidone intermediate in a short synthetic sequence. The sequence to pyrrolidone intermediate is scalable and eludes the use of organometallic pyrophoric reagents on a large scale.
Citation: Synthesis ; : -
PubDate: 2023-07-03T13:22:19+01:00
DOI: 10.1055/s-0042-1751470
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- Concise Total Synthesis of Complanadine A Enabled by
Pyrrole-to-Pyridine Molecular Editing-
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Authors: Martin; Brandon S., Ma, Donghui, Saito, Takeru, Gallagher, Katelyn S., Dai, Mingji
Abstract: The Lycopodium alkaloid complanadine A, isolated in 2000, is a complex and unsymmetrical dimer of lycodine. Biologically, it is a novel and promising lead compound for the development of new treatments for neurodegenerative disorders and persistent pain management. Herein, we report a concise synthesis of complanadine A using a pyrrole-to-pyridine molecular editing strategy. The use of a nucleophilic pyrrole as the precursor of the desired pyridine enabled an efficient and one-pot construction of the tetracyclic core skeleton of complanadine A and lycodine. The pyrrole group was converted into a 3-chloropyridine via Ciamician–Dennstedt one-carbon ring expansion. A subsequent C–H arylation between the 3-chloropyridine and a pyridine N-oxide formed the unsymmetrical dimer, which was then advanced to complanadine A. Overall, from a readily available known compound, the total synthesis of complanadine A was achieved in 11 steps. The pyrrole-to-pyridine molecular editing strategy enabled us to significantly enhance the overall synthetic efficiency. Additionally, as demonstrated by Suzuki–Miyaura cross-coupling, the 3-chloropyridine product from the Ciamician–Dennstedt rearrangement is amenable for further derivatization, offering an opportunity for simplified analogue synthesis.
Citation: Synthesis ; : -
PubDate: 2023-07-03T12:50:36+01:00
DOI: 10.1055/a-2107-5159
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- Base-Promoted 1,6-Aza-Michael Addition of Azauracils to para-Quinone
Methides-
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Authors: Dash; Rupashri, Hota, Sudhir Kumar, Murarka, Sandip
Abstract: We report an efficient higher order conjugate addition of azauracils to substituted para-quinone methides (p-QMs) mediated by triethylamine to furnish hitherto unknown diarylmethane scaffolds through construction of a C–N bond. The protocol features mild conditions, high atom economy, and broad scope, and enables convenient access to biologically relevant new chemical entities (NCEs) comprised of p-QM and azauracil hybrids in good to excellent yields.
Citation: Synthesis ; : -
PubDate: 2023-06-27T14:03:14+01:00
DOI: 10.1055/a-2104-5943
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- Exploiting 1,1-Dibromoalkenes as Direct Precursors to 5-Substituted
1,2,3-Triazoles-
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Authors: Williams; Matthew B., Martin, Matthew L., Wiedmann, Steffen, Boyer, Alistair
Abstract: 1,1-Dibromoalkenes can be used as direct precursors to three classes of 5-substituted 1,2,3-triazoles. Three different approaches to 1,2,3-triazole products were developed, linked to the N1-substituent. Treatment of 1,1-dibromoalkenes with n-butyllithium and reaction with a sulfonyl azide gave 5-substituted 1-sulfonyl-1,2,3-triazoles. The use of lithium base followed by transmetalation to zinc and reaction with aryl azides allowed access to 1-aryl-1,2,3-triazoles. Finally, the use of EtMgBr as base and reaction with an alkyl azide formed 1-alkyl-1,2,3-triazoles.
Citation: Synthesis ; : -
PubDate: 2023-06-27T13:45:12+01:00
DOI: 10.1055/s-0042-1751464
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- Boryl Radical-Promoted Deoxygenative Alkylation of Benzyl Acetates
-
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Authors: Liu; Nan-Nan, Wan, Xuan-Chen, Hui, Li-Wen, Zhang, Feng-Lian, Wang, Yi-Feng
Abstract: Deoxygenative alkylation of benzyl alcohols was realized by using acetate as the alcohol activation group. The C–O bond homolysis is achieved by a boryl radical-promoted β-scission process. The strategy is amenable to a variety of benzyl alcohols, including primary, secondary, and more challenging tertiary alcohols. The synthetic practicability was demonstrated by a gram-scale one-pot reaction.
Citation: Synthesis ; : -
PubDate: 2023-06-27T11:05:20+01:00
DOI: 10.1055/s-0042-1751463
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- Synthesis of Heterocycles from Donor-Acceptor Cyclopropanes: A Five-Year
Recap-
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Authors: Deepthi, Ani, B; Meenakshy C., Mohan, Maneesh
Abstract: This review discusses the utility of donor-acceptor cyclopropanes (DACs) for the construction of heterocycles. In addition to (3+2), (3+3), and (4+3) cycloaddition pathways, nucleophilic ring-opening reactions, intramolecular transformations, and cycloisomerizations in the presence of suitable catalysts pave the way for the generation of heterocycles from DACs. The mild reactions conditions employed and the variety of starting materials that can be used as reaction partners make the DAC route for heterocycle synthesis attractive. The literature covered in this review is from the period 2018 to 2023.1 Introduction2 Synthesis of Nitrogen Heterocycles2.1 By Annulations with Anthranils and Azadienes2.2 By Nucleophilic Attack of Anilines and Hydrazones2.3 By Reaction with Ureas and Thioureas2.4 By Annulation Reactions Using an Azomethine Imine2.5 By Reaction with Other Nitrogen Heterocycles2.6 By Other Transformations3 Synthesis of Oxygen Heterocycles3.1 By Intramolecular Transformations3.2 By Intermolecular Reactions4 Synthesis of Sulfur and Selenium Heterocycles4.1 By Reaction with Thiocarbonyl Substrates4.2 By Reaction with Thio- and Selenocyanates and Thiosulfonate Salts5 Synthesis of N–S and N–O Heterocycles6 Conclusions
Citation: Synthesis ; : -
PubDate: 2023-06-26T14:30:08+01:00
DOI: 10.1055/a-2096-4302
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- Manganese-Catalyzed ortho-Hydroalkylation of Aryl-Substituted
N-Heteroaromatic Compounds with Maleimides-
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Authors: Shinde; Vikki N., Bhawani, Bhawani, Nipate, Dhanajay S., Sonam, Sonam, Meena, Neha, Rangan, Krishnan, Kumar, Dalip, Kumar, Anil
Abstract: A regioselective manganese-catalyzed ortho-hydroalkylation of aryl-substituted N-heteroaromatic compounds with a range of maleimides is described. The developed C–H bond functionalization protocol allowed the introduction of the succinimide motif at the ortho-position of the aryl ring of N-heteroaromatic compounds, such as 2-arylimidazo[1,2-a]pyridines, 2-arylindazoles, 2-phenylpyridine, 2-phenylpyrimidine, 2-phenylimidazo[1,2-a]pyrimidine, 2-phenylimidazo[2,1-b]thiazole, 2-phenylbenzo[d]imidazo[2,1-b]thiazole, 1-phenylindazole and 1-phenylpyrazole, to produce 3-(2-(N-heteroaryl)aryl)pyrrolidine-2,5-diones in good yields. The protocol exhibited broad substrate scope, good functional group tolerance and excellent regioselectivity under mild and additive-free reaction conditions.
Citation: Synthesis ; : -
PubDate: 2023-06-26T14:30:01+01:00
DOI: 10.1055/a-2066-1131
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- Exploring Chemical Modifications of Aromatic Amino Acid Residues in
Peptides-
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Authors: Bhunia; Susanta, Purushotham, Manasa, Karan, Ganesh, Paul, Bishwajit, Maji, Modhu Sudan
Abstract: The chemical diversification of biomolecules set forth a significant area of research that constitutes an important intersection between chemistry and biology. Amino acids and peptides are the fundamental building blocks of proteins and play essential roles in all living organisms. While significant efforts have been geared toward the chemical modification of amino acid residues, particularly the functionalization of reactive functional groups such as lysine NH2 and cysteine SH, the exploration of the aromatic amino acid residues of tryptophan, tyrosine, phenylalanine, and histidine has been relatively limited. Therefore, this review highlights strategies for the side-chain functionalization of these four aromatic amino acids in peptides, with a focus on elucidating the underlying mechanisms. We have also illustrated the use of these modifications in the chemical and biological realm.1 Introduction2 Tryptophan Modifications3 Tyrosine Modifications4 Phenylalanine Modifications5 Histidine Modifications6 Perspectives and Future Outlook
Citation: Synthesis ; : -
PubDate: 2023-06-19T14:29:16+01:00
DOI: 10.1055/a-2091-8062
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- CD44 and EGFR Dual-Targeted Antibody-Recruiting Complex Based on
Hyaluronic Acid Grafted with β-Cyclodextrin and Multivalent Rhamnose for
Cancer Immunotherapy-
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Authors: Zheng; Lele, Li, Yanchun, Lin, Han, Hong, Haofei, Shi, Jie, Zhou, Zhifang, Wu, Zhimeng
Abstract: A new generation of multivalent antibody-recruiting molecules (ARMs) with dual-targeting tumor-binding termini (TBT), including hyaluronic acid targeting CD44 and nanobody 7D12 or peptide GE11 targeting EGFR, was constructed for cancer immunotherapy. The 7D12 or GE11 were assembled onto β-cyclodextrin-grafted hyaluronic acid (HACD) with multivalent rhamnose via host-guest interaction to form macromolecule complexes. The immunological studies proved that these complexes had dual-targetability on CD44 and EGFR and the rhamnose on HACD could recruit anti-Rha antibodies to mediate cytotoxicity against the targeted tumor cells. This bispecific ARM strategy provides a platform for cancer immunotherapy.
Citation: Synthesis ; : -
PubDate: 2023-06-14T09:19:17+01:00
DOI: 10.1055/a-2093-3528
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- Palladium-Catalyzed Dearomatization of Benzothiophenes: Isolation and
Functionalization of a Discrete Dearomatized Intermediate-
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Authors: Intelli; Andrew John, Pal, Mohan, Selvaraju, Manikandan, Altman, Ryan A.
Abstract: A Pd-catalyzed decarboxylative dearomatization reaction of a heterocyclic substrate enables access to an uncommon reaction intermediate that rearomatizes in the presence of amine bases in a net C–H functionalization sequence. The dearomatized benzo[b]thiophene intermediate bears an exocyclic alkene that can be functionalized through cycloaddition and halogenation reactions to deliver complex heterocyclic products.
Citation: Synthesis ; : -
PubDate: 2023-06-13T08:14:13+01:00
DOI: 10.1055/a-2092-9012
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- Synthetic Studies toward the Myrioneuron Alkaloids
-
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Authors: Aquilina; Jake M., Smith, Myles W.
Abstract: The Myrioneuron alkaloids are a relatively small family of plant-derived alkaloids that present an intriguing array of structural intricacy and biological properties. As such, these natural products have drawn interest from the synthetic community, resulting in creative total syntheses of several family members. This review showcases recent synthetic efforts towards these polycyclic alkaloids.1 Introduction1.1 Biological Activity1.2 Proposed Biosynthesis2 Synthetic Studies toward the Myrioneuron Alkaloids2.1 Total Synthesis of Myrioxazines A and B2.2 Total Synthesis of Myrionine, Myrionidine, and Schoberine2.3 Total Synthesis of Myrifabrals A and B2.4 Total Synthesis of Myrioneurinol3 Conclusions and Outlook
Citation: Synthesis ; : -
PubDate: 2023-06-12T11:40:14+01:00
DOI: 10.1055/a-2085-5934
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- Selective Deuteration of Heterocycle N-Oxides via Iridium-Catalysed
Hydrogen Isotope Exchange-
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Authors: Owens; Philippa K., Smith, Blair I. P., Campos, Sebastien, Lindsay, David M., Kerr, William J.
Abstract: An iridium(I) N-heterocyclic carbene/phosphine complex has been applied to the C–H activation and hydrogen isotope exchange of quinoline N-oxides. The isotope labelling proceeds under exceptionally low catalyst loadings of 0.25 mol% and delivers products with high levels of deuterium incorporation selectively at the C8 position. A broad substrate scope is demonstrated, with the method tolerant of electron-poor and -rich substrates, and of substitution adjacent to the site of C–H activation. The isotope label is fully retained under standard deoxygenation conditions to give the corresponding labelled quinoline, and the labelling and deoxygenation can be combined in a one-pot procedure.
Citation: Synthesis ; : -
PubDate: 2023-06-01T14:29:04+01:00
DOI: 10.1055/a-2088-4302
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- Convergent Synthesis of the Octasaccharide Repeating Unit of the K55
Capsular Polysaccharide of Acinetobacter baumannii BAL_204 Strain-
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Authors: Sahaji; Samim, Shit, Pradip, Misra, Anup Kumar
Abstract: Synthesis of the octasaccharide repeating unit of the K55 capsular polysaccharide of Acinetobacter baumannii BAL_204 strain has been achieved in very good yield using a convergent [5+3] block glycosylation strategy. The pentasaccharide and trisaccharide components were synthesized using sequential stereoselective glycosylations. The p-methoxybenzyl (PMB) group was used as temporary alkyl protecting group, which was removed under the thiophilic glycosylation condition by raising the temperature. A late-stage TEMPO-mediated selective oxidation of primary hydroxyl group into carboxylic acid allowed getting the d-glucuronic acid moiety in the octasaccharide. A combination of N-iodosuccinimide (NIS) and perchloric acid supported over silica (HClO4-SiO2) was used as a thiophilic promoter for the activation of thioglycosides. HClO4-SiO2 was also used as a solid acid activator for glycosyl trichloroacetimidate derivative.
Citation: Synthesis ; : -
PubDate: 2023-05-30T12:59:18+01:00
DOI: 10.1055/s-0042-1751460
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- A Manufacturing Strategy Utilizing a Continuous-Mode Reactor toward
Homogeneous PEGylated Bioconjugate Production-
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Authors: Nakahara; Yuichi, Endo, Yuta, Takahashi, Kazutoshi, Kawaguchi, Tomoko, Kato, Keisuke, Matsuda, Yutaka, Nagaki, Aiichiro
Abstract: Protein PEGylation is a traditional bioconjugation technology that enhances the therapeutic efficacy and in vivo half-life of proteins by the formation of covalent bonds with highly activated ester group linked polyethylene glycol (PEG). However, the high reactivity of these reagents induces a random reaction with lysine residues on the protein surface, resulting in a heterogeneous mixture of PEGylated proteins. Moreover, the traditional batch-mode reaction has risks relating to scalability and aggregation. To overcome these risks of traditional batch-mode PEGylation, a manufacturing strategy utilizing structural analysis and a continuous-flow-mode reaction was examined. A solvent exposure analysis revealed the most reactive lysine of a protein, and the continuous-flow mode modified this lysine to achieve the mono-PEGylation of two different proteins within 2 seconds. This ultrarapid modification reaction can be applied to the gram-scale manufacturing of PEGylated bioconjugates without generating aggregates. A similar trend of the exposure level of protein lysine and mono-selectivity performed by continuous-flow PEGylation was observed, which indicated that this manufacturing strategy has the potential to be applied to the production of a wide variety of bioconjugates.
Citation: Synthesis ; : -
PubDate: 2023-05-30T12:59:12+01:00
DOI: 10.1055/a-2077-6187
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- Transition-Metal-Free Cross-Coupling of Acetals and Grignard Reagents To
Form Diarylmethyl Alkyl Ethers and Triarylmethanes-
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Authors: Qin; Yang, Liu, Sheng, Shi, Shi-Liang
Abstract: We herein report a transition-metal-free cross-coupling reaction of acetals and Grignard reagents. The method provides a modular preparation of diarylmethyl alkyl ethers, triarylmethanes, and 1,1-diarylalkanes that constitute the core structures of many bioactive molecules and synthetic motifs. A series of readily accessible acetals bearing aryl, alkenyl, and alkyl substituents efficiently coupled with commercially available aryl, alkyl, and allylic magnesium bromides to give the products in high yields. In addition to acyclic and cyclic acetals, ketal and orthoester also serve as viable substrates to afford sterically hindered tertiary ether and ketal respectively. A sequential difunctionalization of acetals led to the rapid synthesis of triarylmethanes and diarylalkanes.
Citation: Synthesis ; : -
PubDate: 2023-05-30T12:59:06+01:00
DOI: 10.1055/a-2088-5000
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- Biocatalytic Synthesis of Chiral Benzylic Alcohols via Enantioselective
Hydroxylation by a Self-Sufficient Cytochrome P450 from Deinococcus
gobiensis-
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Authors: Cui; Hai-Bo, Ma, Ting, Zhang, Ru-Yue, Shan, Jing, Wang, Zhong-Qiang, Bai, Mei, Chen, Yong-Zheng
Abstract: Enzymatic asymmetric benzylic hydroxylation represents a green synthesis of valuable chiral benzylic alcohols. The stereoselective C–H direct hydroxylation profile possessed by cytochrome P450 monooxygenases (P450s) makes it more attractive. Here, we successfully expressed a self-sufficient cytochrome P450 monooxygenase from Deinococcus gobiensis in Escherichia coli BL21(DE3) host. The recombinant E. coli (P450DG) strain performed well in terms of functionality and has stereoselective benzylic hydroxylation ability for propylbenzene substrates. Asymmetric benzylic hydroxylation of various aromatic compounds was further investigated using the recombinant E. coli (P450DG) strain based on the optimal conditions, producing the corresponding enantioenriched pharmaceutically relevant benzylic alcohols in moderate yields with good to excellent enantioselectivity.
Citation: Synthesis ; : -
PubDate: 2023-05-23T09:46:01+01:00
DOI: 10.1055/a-2076-9792
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- Chemoenzymatic Synthesis of arabino-Configured Bicyclic Nucleosides
-
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Authors: Singla; Harbansh, Maity, Jyotirmoy, Kumar, Sandeep, Kavita, Kavita, Chaudhary, Riya, Prasad, Ashok K.
Abstract: A convergent route for the synthesis of a new class of bicyclic nucleosides has been developed. The synthetic route to the corresponding arabino-configured uracil and thymine bicyclic nucleosides proceeds in 24 and 27% overall yields, respectively, starting from 1,2,5,6-di-O-isopropylidene-α-d-glucofuranose. This synthetic protocol includes some crucial steps such as Vorbrüggen base coupling and chemo-enzymatic regioselective acetylation of the primary hydroxyl group by using Lipozyme® TL IM where it was found that Lipozyme® TL IM could be recovered and reused for selective acetylation without losing its selectivity.
Citation: Synthesis ; : -
PubDate: 2023-05-22T14:43:11+01:00
DOI: 10.1055/s-0041-1738440
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- An Effective Additive for Introducing the Triazole Unit of Ensitrelvir:
Combination of LiCl and Et3N to Easily Generate Lithium Triazinolate-
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Authors: Ohashi; Eisaku, Sahara, Naoto, Hirano, Yoichi, Hosoya, Masahiro, Takahashi, Yusaku, Tsuno, Naoki
Abstract: An efficient and robust method was developed to introduce the triazole unit of Ensitrelvir, a COVID-19 therapeutic agent. One of the key steps is introducing the triazole unit in the triazinone with Cs2CO3 and KI in a heterogeneous system. Detailed reaction screening revealed that addition of LiCl allowed the reaction to proceed quantitatively in the presence of inexpensive Et3N, and the selectivity of the N-alkylation was greatly improved. The key to promoting the reaction is the mild formation of the lithium triazinolate accompanied by precipitation of Et3N·HCl (the only insoluble matter in this reaction). Dissolving all the substrates and reagents should contribute to further improvement of the process robustness.
Citation: Synthesis ; : -
PubDate: 2023-05-22T13:13:08+01:00
DOI: 10.1055/a-2085-6342
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- Pd(II)-Catalyzed Directing-Group-Aided C–H Arylation, Alkylation,
Benzylation, and Methoxylation of Carbazole-3-carboxamides toward
C2,C3,C4-Functionalized Carbazoles-
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Authors: Kaur; Ramandeep, Singh, Harcharan, Babu, Srinivasarao Arulananda
Abstract: We report the Pd(II)-catalyzed β-C–H arylation, alkylation, benzylation, and methoxylation of carbazole-3-carboxamide and carbazole-2-carboxamide substrates, assisted by the bidentate directing groups 8-aminoquinoline or 2-(methylthio)aniline, and construction of C2,C3,C4-functionalized carbazole motifs. The Pd(II)-catalyzed β-C–H arylation reaction was attempted using different directing groups such as 8-aminoquinoline, 2-(methylthio)aniline, 4-amino-2,1,3-benzothiadiazole, 4-methoxyquinolin-8-amine, and butan-1-amine. Through optimization of the reactions, 8-aminoquinoline and 2-(methylthio)aniline were found to be suitable directing groups and, especially, 2-(methylthio)aniline was found to be an efficient directing group in the Pd(II)-catalyzed β-C–H arylation, alkylation, and methoxylation of carbazole-3-carboxamide, carbazole-2-carboxamide substrates. An ample number of β-C–H arylated, alkylated, benzylated, and methoxylated carbazole-3-carboxamides were synthesized. The structures of representative β-C(2)–H arylated carbazole and β-C(2)–H methoxylated carbazole motifs were unequivocally confirmed by single-crystal X-ray structure analysis. Given the wide range of applications of carbazoles in chemistry, materials sciences, and medicinal chemistry and there have been constant efforts for developing new methods for synthesizing functionalized carbazoles. This work contributes to the expansion of the library of C2,C3,C4-functionalized carbazole motifs through a Pd(II)-catalyzed directing-group-aided site-selective β-C–H activation and functionalization of carbazole-3-carboxamides.
Citation: Synthesis ; : -
PubDate: 2023-05-08T11:29:37+01:00
DOI: 10.1055/a-2056-2363
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- Recent Applications of Ammonium Ylide Based [2,3]-Sigmatropic and
[1,2]-Stevens Rearrangements To Transform Amines into Natural Products-
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Authors: Schwartz; Zachary, Valiton, Chelsea, Lovasz, Myles, Roberts, Andrew G.
Abstract: Ammonium ylide based [2,3]-sigmatropic and [1,2]-Stevens rearrangements enable the transformation of tertiary amines into rearranged and functionalized intermediates en route to many polycyclic natural product targets. Herein, we summarize recent applications of these rearrangement reactions in formal and total synthesis endeavors while highlighting innovative improvements to these transforms.1 Introduction2 Ammonium Ylide Based [2,3]-Sigmatropic Rearrangements in Natural Product Synthesis2.1 (–)-Cephalotaxine2.2 (±)-Amathaspiramide F2.3 (–)-Cephalezomine G and Its C3 Epimer2.4 (±)-Strictamine2.5 (–)-Doxycycline3 [1,2]-Stevens Rearrangements Toward Natural Products3.1 Ring-Expanding [1,2]-Stevens Rearrangements en route to (±)-Tylophorine, (±)-7-Methoxycryptopleurine, and (±)-Xylopinine3.2 Enantioselective Synthesis of Iboga Alkaloids and (+)-Vinblastine4 Selected Methodology4.1 Ammonium Ylide Based [2,3]-Sigmatropic Rearrangements To Form Natural Product Cores4.2 Cascade Reactions Involving [1,2]-Stevens Rearrangement/ Hofmann-Type Elimination Events5 Conclusions
Citation: Synthesis ; : -
PubDate: 2023-05-04T13:57:33+01:00
DOI: 10.1055/s-0042-1751446
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- Pd-Nanoparticles-Catalyzed C(sp2)–H Arylation for the Synthesis of
Functionalized Heterocycles: Recent Progress and Prospects-
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Authors: Sunny, Steeva, Maingle, Mohit, Sheeba, Loddipalle, Pathan, Firojkhan Rajekhan, J; Gowri Sankar, Juloori, Harika, Gadewar, Sainath Ganesh, Seth, Kapileswar
Abstract: Transition-metal-nanoparticles-catalyzed C–H activation/functionalization is a prominent topic in contemporary research, enabling the functionalization of privileged heterocyclic scaffolds that hold a significant space in the scientific community due to their immense applications in materials science and in medicinal, natural product, and agricultural chemistry. Among transition-metal-based nanoparticles, Pd nanoparticle catalysis has emerged as the most attractive tool for promoting a wide array of practical synthetic transformations of heterocycles. In the last few years, the catalytic application of Pd nanoparticles in C–H functionalization has gained popularity in generating relatively inaccessible bonds with a high degree of selectivity and efficiency via the activation of surface metal atoms at the nanoscale level. The quantum size effect of nanoparticles offers a large surface area, with typically many easily accessible active sites/unit areas. These unique characteristics of nanoparticles are considered primary factors of enhanced catalytic activity compared to bulk materials. The nanoparticle catalysts anchored on solid-supports plus unsupported types (e.g., magnetic nanoparticles) allow easy separation from the reaction mixture, enabling recycling multiple times, which contributes notably to sustainable management and cost efficiency of a production process. In the current review, we discuss Pd-nanoparticles-catalyzed C(sp2)–H arylation for the synthesis of functionalized heterocycles, covering literature reports from 2010 to 2021. The preparation of Pd nanoparticles and the mechanistic realizations in their corresponding reactions are also explained briefly.1 Introduction2 Arylation of Heterocyclic Scaffolds2.1 Synthesis of Functionalized Indole Derivatives2.2 Synthesis of Functionalized (Benzo)thiazole/Benzoxazole Derivatives2.3 Synthesis of Functionalized Triazoles2.4 Synthesis of Functionalized Pyridines and Related Scaffolds2.5 Synthesis of Functionalized Furan, Thiophene and N-Methylpyrrole Scaffolds2.6 Synthesis of Functionalized Multiple Heterocycles via Single-Step Strategies3 Conclusions
Citation: Synthesis ; : -
PubDate: 2023-05-03T15:33:30+01:00
DOI: 10.1055/a-2060-3488
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- Recent Advances in the Synthesis and Application of C-2-Formyl Glycals
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Authors: Arora; Aditi, Kumar, Sumit, Khatri, Vinod, Prasad, Ashok K., Chhatwal, Rajni Johar, Kumar, Sandeep
Abstract: C-2-Formyl glycals have sustained interest in carbohydrate chemistry as they afford valuable chiral building blocks for many biological-, pharmaceutical-, and industrial-based important molecules. Basically, C-2-formyl glycals are a class of carbohydrates incorporating an α,β-unsaturated aldehyde. Therefore in many organic reactions, the C-2-formyl glycals can serve as an α,β-unsaturated aldehyde core. In this review, we have compiled a literature survey covering the period 2013–2022, on the synthesis of C-2-formyl glycals and further discuss their importance for the synthesis of many medicinal, supramolecular, biological, organic, and material chemistry based molecules.1 Introduction2 Synthesis of C-2-Formyl Glycals2.1 Vilsmeier–Haack Formylation2.2 By Consecutive Cyclization2.3 XtalFluor‑E Based Synthesis3 Applications of C-2-Formyl Glycals3.1 C-2-Formyl Glycals as a Synthons3.2 Anticancer3.3 Anti-inflammatory3.4 Antimicrobial3.5 Glycosidase Inhibitors3.6 Miscellaneous4 Conclusion and Future Aspects
Citation: Synthesis ; : -
PubDate: 2023-05-02T15:09:51+01:00
DOI: 10.1055/a-2066-1659
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- Decarboxylative Alkenylation of Imidazo[1,2-a]pyridines Using
α,β-Unsaturated Carboxylic Acids via Pd-Catalyzed C–H
Functionalization-
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Authors: Kumar; Saurabh, Prabhakar, Neha Sharma, Kishor, Kaushal, Singh, Krishna Nand
Abstract: An efficient synthesis of alkenylated imidazo[1,2-a]pyridines has been accomplished using imidazo[1,2-a]pyridines and α,β-unsaturated carboxylic acids adopting C–H functionalization strategy in the presence of palladium acetate, 1,10-phenanthroline, and silver carbonate.
Citation: Synthesis ; : -
PubDate: 2023-04-27T11:46:50+01:00
DOI: 10.1055/a-2067-4041
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- Transition-Metal-Catalyzed Directed C8–H Carbon–Carbon Bond Formation
in Quinolines and 1,2,3,4-Tetrahydroquinolines-
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Authors: Basak; Shubhajit, Paul, Tripti, Mandal, Santu, Karjee, Pallab, Nanjegowda, Maniya Vadakanamala, Punniyamurthy, Tharmalingam
Abstract: C8-Substituted quinoline (QN) and 1,2,3,4-tetrahydroquinoline (THQ) scaffolds are featured in numerous bioactive compounds and natural products. Appreciable efforts have been made towards the development of elegant techniques to functionalize the C8–H bond of QNs and THQs. The transition-metal-catalyzed chelation-assisted C–H activation strategy has emerged as an effective synthetic tool among existing methods. This review focuses on recent advances in transition-metal-catalyzed directed carbon–carbon bond forming reactions for the C8–H functionalization of QNs and THQs (till February 2023). The discussion has been categorized based on the type of reaction.1 Introduction2 Acylation3 Alkylation4 Alkenylation5 Alkynylation6 Allylation7 Annulation8 Arylation9 Conclusion and Outlook
Citation: Synthesis ; : -
PubDate: 2023-04-25T14:10:14+01:00
DOI: 10.1055/a-2058-0695
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- Oxidative C–N Bond Cleavage of Cyclic Amines with Ammonium
Hypochlorite-
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Authors: Kaieda; Yuya, Yamamoto, Kosuke, Toguchi, Hiroyuki, Hanazawa, Natsumi, Kuriyama, Masami, Onomura, Osamu
Abstract: An oxidative C–N bond cleavage of cyclic amines has been developed under metal-free conditions, providing N-Cl-ω-amino acids in moderate to excellent yields. The reactions proceed by using tetramethylammonium hypochlorite (TMAOCl) as an oxidant even on a gram scale. Hofmann–Löffler–Freytag-type reaction of N-Cl-ω-amino acids to form cyclic amino acids has also been demonstrated.
Citation: Synthesis ; : -
PubDate: 2023-04-24T14:29:59+01:00
DOI: 10.1055/a-2062-8680
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- An Intramolecular Radical C–N Coupling by N-Iodosuccinimide
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Authors: Bera; Shyamal Kanti, Bhanja, Rosalin, Sahu, Chandan Chittapriya, Mal, Prasenjit
Abstract: A useful method for the formation of benzimidazole-fused phenanthridines through an intramolecular coupling of unactivated C(sp2)–H and N(sp3)–H bonds using N-iodosuccinimide (NIS) in trifluoroethanol (TFE) is presented. The synthesis of benzo[4,5]imidazo[1,2-f]phenanthridines from 2-([1,1′-biphenyl]-2-yl)-1H-benzo[d]imidazole derivatives is mild, efficient, and sustainable, with high yields and minimal waste generation. The control experiments and EPR studies were aimed at rationalizing the radical pathway of the reaction. Specifically, the use of 1,1-diphenylethylene, TEMPO, BHT, and DMPO as a free-radical spin-trapping reagent in EPR studies, allowed us to conceive a radical pathway. The gram-scale synthesis further supported the practical utility of the methodology for the field of synthetic chemistry.
Citation: Synthesis ; : -
PubDate: 2023-04-20T14:45:46+01:00
DOI: 10.1055/a-2063-0221
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- Copper-Catalyzed Carbonylative Cross-Coupling of Alkyl Iodides with
Alcohols and Sodium Hydroxide: Synthesis of Esters and Carboxylic Acids-
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Authors: Adaoudi; Omaïma, Le Bescont, Julie, Bruneau-Voisine, Antoine, Evano, Gwilherm
Abstract: A general and inexpensive catalytic system is reported for the copper-catalyzed carbonylative coupling between alkyl iodides and alcohols or sodium hydroxide. Upon reaction with catalytic amounts of copper(I) chloride and N,N,N′,N′′,N′′-pentamethyldiethylenetriamine under a mild pressure of carbon monoxide (5 bar), a range of secondary and tertiary alkyl iodides are readily converted into the corresponding esters and carboxylic acids without competing direct nucleophilic substitution. Main advantages of this procedure include its broad applicability, the use of an especially inexpensive and available catalytic system, and its user-friendliness.
Citation: Synthesis ; : -
PubDate: 2023-04-19T09:45:56+01:00
DOI: 10.1055/a-2042-3417
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- On the Reaction Mechanism of the Selective C(sp3)–H Functionalization of
N-Benzylpiperidines Mediated by TEMPO Oxoammonium Cation-
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Authors: Romero-Ibañez; Julio, Sandoval-Lira, Jacinto, Cruz-Gregorio, Silvano, Hernández-Pérez, Julio M., Quintero, Leticia, Sartillo-Piscil, Fernando
Abstract: The selective and dual C(sp3)–H oxidation of N-heterocycles to their corresponding 3-alkoxyamino lactams mediated by TEMPO oxoammonium cation (TEMPO+) is turning into a convenient nonmetallic strategy for the rapid functionalization of piperidines and pyrrolidines to bioactive alkaloids. Mechanistic proposal suggests that TEMPO+ prefers to oxidize the endocyclic C–Hα bond of either N-substituted piperidines or pyrrolidines to their corresponding endocyclic iminium intermediates, which are transformed into enamine intermediates, and then trapped by oxoammonium cation. Although the product formation seems to be in concordance with this mechanistic rationale, neither experimental evidence nor theoretical calculations have been reported. Accordingly, the current investigation provides computational findings explaining that the origin of the selective C–Hα oxidation can be attributed to an unprecedented C–H···π interaction between two hydrogen atoms of TEMPO+ with the aromatic ring of the piperidine benzyl group. To prove the existence of the enamine intermediate, we developed an unprecedented transition-metal-free tetra C–H oxidation of two N-benzyl-4-methylenepiperidines. Accordingly, the existence of the elusive enamine intermediate was attained by generating a transitory dienamine intermediate, which was trapped by TEMPO+ and NaClO2 to give the corresponding 4-(aminooxymethyl)-3,4-epoxy-2-piperidone.
Citation: Synthesis ; : -
PubDate: 2023-04-18T15:25:34+01:00
DOI: 10.1055/a-2053-9558
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- Palladium-Catalyzed Regioselective C-Arylation and C,N-Diarylation of
N-Aryl-2,3-dihydrophthalazine-1,4-diones Using Diaryliodonium Salts-
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Authors: Naharwal; Sushma, Kharat, Narendra Dinkar, Mahesha, Chikkagundagal K., Bajaj, Kiran, Sakhuja, Rajeev
Abstract: Regioselective C-arylation and C,N-diarylation in 2-aryl-2,3-dihydrophthalazine-1,4-diones has been successfully accomplished with diaryliodonium salts under base-mediated slightly modified Pd-catalyzed conditions. These ligand-driven transformations provided a variety of diversely decorated bi(hetero)aryls in good-to-excellent yields, while N-arylated product could be obtained under similar Pd-catalyzed conditions in the absence of a ligand.
Citation: Synthesis ; : -
PubDate: 2023-04-13T13:21:54+01:00
DOI: 10.1055/a-2048-8030
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- Synthesis of Ledipasvir through a Late-Stage Cyclopropanation and
Fluorination Process-
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Authors: Ramu; Chennam, Kumaraguru, T., Reddy, M. Sridhar, Rode, Haridas B., Ghosh, Subhash, Reddy, Ch. Raji, Sudhakar, Gangarajula
Abstract: We have designed and developed an easily accessible advanced intermediate of ledipasvir that allowed late-stage cyclopropanation and difluorination, thereby providing a novel and more efficient process for the preparation of ledipasvir in the longest linear sequence of 8 steps with 20% overall yield.
Citation: Synthesis ; : -
PubDate: 2023-04-13T09:49:12+01:00
DOI: 10.1055/s-0042-1751437
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- C6–H Bond Functionalization of Indoles: A New Gate
-
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Authors: Taskesenligil; Yunus, Saracoglu, Nurullah
Pages:
Citation: Synthesis ; : -
PubDate: 2023-04-12T12:43:33+01:00
DOI: 10.1055/a-2050-4897
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- Dealkenylative Functionalizations: Conversion of Alkene C(sp3)–C(sp2)
Bonds into C(sp3)–X Bonds via Redox-Based Radical Processes-
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Authors: Dehnert; Brady W., Dworkin, Jeremy H., Kwon, Ohyun
Abstract: This review highlights the history and recent advances in dealkenylative functionalization. Through this deconstructive strategy, radical functionalizations occur under mild, robust conditions. The reactions described proceed with high efficiency, good stereoselectivity, tolerate many functional groups, and are completed within a matter of minutes. By cleaving the C(sp3)–C(sp2) bond of terpenes and terpenoid-derived precursors, rapid diversification of natural products is possible.1 Introduction2 Mechanism3 History4 Motivation to Pursue Dealkenylation5 Dealkenylation in the Present6 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-04-12T09:21:23+01:00
DOI: 10.1055/a-2044-4571
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- Photocatalyst-Free, Visible-Light-Mediated C–H Perfluoroalkylation of
Quinazolin-4(3H)-ones with perfluoroalkyl Iodides-
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Authors: Delouche; Thomas, Gadiry-Diallo, Abdoul, Besson, Thierry, Ogoshi, Sensuke, Fruit, Corinne
Pages:
Citation: Synthesis ; : -
PubDate: 2023-04-11T12:03:15+01:00
DOI: 10.1055/a-2054-0482
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- Gold-Catalyzed Cyclization of Alkynyl Heteroarenes with a Norbornene
Bridge-
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Authors: Jeon; Ju Eun, Jeong, Siyeon, Kwak, Hayeon, Joo, Jung Min
Pages:
Citation: Synthesis ; : -
PubDate: 2023-03-27T09:51:20+01:00
DOI: 10.1055/a-2039-5521
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- Bimetallic Catalyzed Synthesis of 2-Arylindoles
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Authors: Ferro; Rita, Viduedo, Nuno, Santos, A. Sofia, Silva, Artur M. S., Royo, Beatriz, Marques, M. Manuel B.
Abstract: A bimetallic synthesis of 2-arylindoles from alcohols and anilines is described. The dehydrogenation or oxidation of a secondary alcohol was performed by Ni- or Mn-catalyzed reactions, respectively. The formed ketone was converted into an imine intermediate that was later cyclized to the corresponding 2-arylindole by a Pd-catalyzed oxidative cyclization. A series of 2-arylindoles were prepared without isolation of the intermediates generated. The compatibility of the catalysts was investigated, and the optimized protocol opens room for the integration of Earth-abundant metals and palladium complexes to improve the sustainability of the synthesis of N-heterocycles.
Citation: Synthesis ; : -
PubDate: 2023-03-17T11:05:18+0100
DOI: 10.1055/a-2035-6420
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- Aryl Triflates in Phosphorus-Directed Rhodium(III)-Catalyzed C–H
Activation-
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Authors: Roger; Julien, Sire, Charline, Tsivery, Anthonia, Cattey, Hélène, Hierso, Jean-Cyrille
Abstract: Aryl triflates are selected as suitable electrophile coupling partners for the phosphorus-directed rhodium(III)-catalyzed direct C–H arylation of polyaromatic phosphines. We report herein simple conditions for the peri-C–H functionalization of polyarylphosphines, where a [Rh(III)Cl2Cp*]2 precatalyst is employed to provide a convenient access to polyarylated phosphines in up to 93% isolated yield. This synthetic approach tolerates a wide range of different aryl trifluoromethylsulfonate derivatives bearing either electron-donating (COMe, CN, CF3 or Cl) or electron-withdrawing substituents (Me, OMe) at the para-, meta- and ortho-positions, and includes bulky polyaromatic triflate substrates. We further describe access to a large class of polycyclic aromatic hydrocarbon phosphine ligands, their oxidized derivatives (i.e., their oxides and selenides), their coordination modes with Au(I) and Cu(I) coinage metal salts, and their use as efficient ligands for the atom-economic, gold-catalyzed oxidative cyclization of terminal alkynes with nitriles.
Citation: Synthesis ; : -
PubDate: 2023-03-14T14:19:33+0100
DOI: 10.1055/a-2018-0965
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- Elements-Continuous-Flow Platform for Coupling Reactions and Anti-viral
Daclatasvir API Synthesis-
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Authors: Mahajan; Bhushan, Aand, Dnyaneshwar, Purwa, Mandeep, Mujawar, Taufiqueahmed, Ghosh, Subhash, Pabbaraja, Srihari, Singh, Ajay K.
Pages:
Citation: Synthesis ; : -
PubDate: 2023-03-07T14:43:45+0100
DOI: 10.1055/a-2022-2063
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- Palladium-Catalyzed Unimolecular Fragment Coupling of N-Allylamides
Bearing a Tethered Nucleophile with the Translocation of an Amide Group-
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Authors: Shimazumi; Ryoma, Kodama, Takuya, Tobisu, Mamoru
Pages:
Citation: Synthesis ; : -
PubDate: 2023-03-06T14:39:27+0100
DOI: 10.1055/a-2022-1905
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- Palladium-Catalyzed C7–H (Hetero)arylation of Pyrazolo[1,5-a]pyrazines
with Heteroarenes and Aryl Iodides with the Assistance of Silver Salts-
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Authors: Nguyen; Thanh V. Q., Levoin, Armand, Poli, Lorenzo
Pages:
Citation: Synthesis ; : -
PubDate: 2023-03-06T11:39:49+0100
DOI: 10.1055/s-0041-1738433
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- Synthesis of 1-Thiaphenalene Derivatives via Radical Cyclization of
1-Naphthalenesulfonyl Chlorides with Alkynes-
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Authors: Wei; Youhao, Liu, Jige, Wu, Xinxin, Chen, Yasu, Zhu, Chen
Pages:
Citation: Synthesis ; : -
PubDate: 2023-03-02T11:07:10+0100
DOI: 10.1055/a-2020-8828
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- Construction of Thienopyrroles through Rhodium-Catalyzed Direct Annulation
of (Acetylamino)thiophenes with Alkynes-
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Authors: Hayashi; Mikishiro, Michikita, Ryudai, Usuki, Yoshinosuke, Satoh, Tetsuya
Abstract: The direct annulative coupling of 3-(acetylamino)thiophenes with internal alkynes proceeds smoothly under rhodium catalysis through acetylamino-directed C–H bond cleavage at the C2-position, leading to the effective construction of 4-acetylthieno[3,2-b]pyrrole derivatives. The acetyl directing group on the annulation product is readily removed to produce the 4-unprotected thieno[3,2-b]pyrrole derivative.
Citation: Synthesis ; : -
PubDate: 2023-02-20T12:46:33+0100
DOI: 10.1055/a-2015-4466
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- Recent Advances in the Dearomative Skeletal Editing of Mono-azaarenes
-
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Authors: Zhang; Pengke, Hua, Lin, Takahashi, Tamotsu, Jin, Shengnan, Wang, Qilin
Abstract: Despite its challenges, the skeletal editing of mono-azaarenes (pyridines, quinolines, and isoquinolines) has shown unparalleled synthetic utility in the construction of complex molecules that are difficult to access by conventional methods. In this short review, we summarize the three most recently developed skeletal editing strategies for the deconstruction of azaarene cores, with a focus on their generality, limitations, and mechanistic aspects. Also, the application of the skeletal editing strategy in the total synthesis of some important natural products is discussed.1 Introduction2 Skeletal Editing of Mono-Azaarenes through Zincke-like Reactions3 Skeletal Editing of Mono-azaarenes through Aza-Buchner Reactions4 Skeletal Editing of Mono-azaarenes via Photoinduced Radical or Energy-Transfer Processes5 Conclusion
Citation: Synthesis ; : -
PubDate: 2023-02-16T12:04:17+0100
DOI: 10.1055/a-2013-9885
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- Regio- and Diastereoselective Synthesis of Substituted Triazolo
[3,4-b]thiadiazin-6-ols and Triazolo[3,4-b]thiadiazines-
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Authors: Mohammadlou; Mahsa, Halimehjani, Azim Ziyaei
Abstract: An efficient, catalyst-free, regio- and diastereoselective approach for the synthesis of novel 7-aryl-3-alkyl(aryl)-6-methyl-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-ols has been developed via the reaction of 4-amino-[1,2,4]triazole-3-thiols with nitroepoxides in methanol at room temperature. The products were simply dehydrated in the presence of PTSA in ethanol at 70 °C to afford the corresponding 7-aryl-3-alkyl(aryl)-6-methyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines in 91–98% yields. In addition, treatment of the product with acidic chloroform afforded the corresponding α-((4-amino-5-methyl-4H-1,2,4-triazol-3-yl)thio)-α-phenylpropan-2-one in quantitative yield.
Citation: Synthesis ; : -
PubDate: 2023-02-15T13:23:37+0100
DOI: 10.1055/a-2017-4814
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- A Concise Total Synthesis of (±)-Stepharine and
(±)-Pronuciferine-
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Authors: Chen; Ruiming, Jia, Shihu, Man, Yuning, Cheng, Hong-Gang, Zhou, Qianghui
Abstract: A concise total synthesis of (±)-stepharine and (±)-pronuciferine using readily available reagents as the starting materials is reported. This synthesis features a three-component Catellani reaction/Au-catalyzed 6-exo-dig cyclization for the assembly of 1-methylene-tetrahydroisoquinoline scaffold and an oxidative dearomatization for constructing spiro-cyclohexadienone scaffold.
Citation: Synthesis ; : -
PubDate: 2023-02-06T13:31:33+0100
DOI: 10.1055/a-1984-0755
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- A Robust, Gram-Scale and High-Yield Synthesis of MDP Congeners for
Activation of the NOD2 Receptor and Vaccine Adjuvantation-
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Authors: Khan; Farooq-Ahmad, Yaqoob, Sana, Qasim, Muhammad Wasim, Ali, Shujaat, Wang, Yan, Jiang, Zi-Hua
Abstract: The bacterial peptidoglycan (PGN) constituent muramyl dipeptide (MDP) and its congeners possess immuno-adjuvant activity, and find applications in vaccines to potentiate the immune response of antigens. It confers non-specific resistance towards pathogenic infections and defense against tumors. In this work, the parent MDP molecule is re-designed by replacing its carbohydrate moiety with an immunoregulatory xanthine scaffold, while conserving the l-d configuration of the pharmacophore. Alkyl chains are introduced at the C-terminus of d-isoglutamine to help the molecules access cytoplasmic NOD2 receptors and activate the innate immune system. Lipophilic MDP congeners are thus obtained by adopting a direct or indirect convergent synthetic route with overall yields of >50%. We found that an indirect approach can reliably be implemented on gram scale, thereby unlocking access to substantial amounts of pathogen-associated molecular patterns for in vivo studies, which will accelerate the development of NOD2 immuno-adjuvants against viral and bacterial infections.
Citation: Synthesis ; : -
PubDate: 2023-02-02T11:19:27+0100
DOI: 10.1055/a-2004-5883
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- Rh(III)-Catalyzed Stereoselective C–H Homoallylation of Indolines with
4-Vinyl-1,3-dioxan-2-ones-
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Authors: Zhang; Zhou, Yi, Jun-Jie, Aslam, Muhammad, Wan, Jie-Ping, Sun, Meng
Abstract: An efficient and robust Rh(III)-catalyzed C–H homoallylation of indolines has been developed. Using 4-vinyl-1,3-dioxan-2-one as coupling partner, a range of homoallylic alcohols were prepared in excellent stereoselectivities. The current strategy features high efficiency, good yields, and exceptional functional group tolerance.
Citation: Synthesis ; : -
PubDate: 2023-01-16T11:24:19+0100
DOI: 10.1055/a-2002-5931
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- Recent Advances in the Asymmetric Doyle–Kirmse Reaction
-
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Authors: Shi; Chong-Yang, Zhou, Bo, Teng, Ming-Yu, Ye, Long-Wu
Pages:
Citation: Synthesis ; : -
PubDate: 2023-08-10T11:50:35+01:00
DOI: 10.1055/a-2119-5390
Issue No: Vol.
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- Visible-Light-Induced Metal-Free Selenation of Tryptamines/3-Substituted
Indoles-
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Authors: Singh; Shashank, Naskar, Kalyan S., Kundu, Arindam, Singh, Ravi P.
Pages:
Citation: Synthesis ; : -
PubDate: 2023-08-09T08:54:26+01:00
DOI: 10.1055/a-2112-2353
Issue No: Vol.
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- Rh-Catalyzed C–H Functionalization of the (Pyrazol-5-yl)pyridine
Core of GBT-440-
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Authors: Kalshetti; Rupali G., Halnor, Swapnil V., Ramana, Chepuri V.
Pages:
Citation: Synthesis ; : -
PubDate: 2023-08-08T09:39:39+01:00
DOI: 10.1055/a-2116-6734
Issue No: Vol.
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