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- Zinc Acetate Catalyzed Stereoselective 1,2-trans-Glycosylation Using
Glycosyl Chlorides
Authors: Ali; Mohammad Saif, Ramesh, P. I., Ghosh, Subhash, Babu Tatina, Madhu
Pages: 219 - 226
Abstract: We report a strategy for the stereoselective synthesis of 1,2-trans-glycosides in the absence of neighboring group participation. The present protocol for the selective glycosylation mainly relies on catalyst control rather than protecting group selection. By using this protocol, several glycosides were prepared. Zinc acetate was found to be the optimal catalyst, providing the desired 1,2-trans-glycosides from glucose- and mannose-derived glycosyl halides at room temperature instead of low-temperature conditions.
Citation: SynOpen 2022; 06: 219-226
PubDate: 2022-10-12T19:49:23+01:00
DOI: 10.1055/a-1941-3801
Issue No: Vol. 06, No. 04 (2022)
- Total Synthesis of Marine-Derived Azole Resistant Antifungal Agent
(–)-Melearoride A and Antibiotic (–)-PF1163B
Authors: Yasam; Bharath Kumar, Pabbaraja, Srihari
Pages: 227 - 237
Abstract: A flexible stereoselective and convergent cum divergent approach to the synthesis of two 13-membered macrolides through a common skeleton present in their structure is described featuring two different routes, with good overall yield. The key synthetic reactions utilized include Keck allylation, Evans asymmetric methylation, Grubbs metathesis, and Julia–Kocienski olefination.
Citation: SynOpen 2022; 06: 227-237
PubDate: 2022-10-12T19:49:23+01:00
DOI: 10.1055/a-1942-6969
Issue No: Vol. 06, No. 04 (2022)
- Approaches to the Total Synthesis of Conduramines: A Review
Authors: Bharathkumar; Hanumantharayappa, Krishna, Jattuboyina Siva, Surender, Banothu, Batchu, Venkateswara Rao
Pages: 238 - 257
Abstract: This review reports on the total synthesis of conduramines, which are formally derived from conduritols, mainly containing a trihydroxy aminocyclohexene core. Analysis of the different strategies developed to prepare these aminocyclohexene triols and their derivatives has been carried out with special attention paid to the methods employed for the insertion of the chiral amine moiety.
Citation: SynOpen 2022; 06: 238-257
PubDate: 2022-10-13T11:28:57+01:00
DOI: 10.1055/a-1933-0602
Issue No: Vol. 06, No. 04 (2022)
- A Practical and Economical Route to (S)-Glycidyl Pivalate
Authors: Noble; Jeffrey M., Chang, Le, Chen, Dan, Wang, Binglin, Dominey, Raymond N., Cook, Daniel W., Burns, Justina M., Stringham, Rodger W., Cardoso, Flavio S. P., Snead, David R.
Pages: 258 - 262
Abstract: An efficient method to prepare enantiopure (S)-glycidyl pivalate from (R)-epichlorohydrin and pivalic acid is reported. This work provides an alternative to the synthesis of this important building block from readily available and inexpensive materials.
Citation: SynOpen 2022; 06: 258-262
PubDate: 2022-10-19T13:40:59+01:00
DOI: 10.1055/s-0042-1751375
Issue No: Vol. 06, No. 04 (2022)
- Zn/ZnBr2 Catalysed Reaction of Aldehydes with Allylbromide: Synthesis of
2,6-Disubstituted 4-Bromotetrahydropyrans
Authors: Biradar; D. O., Mane, Y. D., Sarnikar, Y. P., Kulkarni, S. G., Reddy, B. V. Subba, Narsaiah, A. Venkat
Pages: 263 - 269
Abstract: An efficient approach for the one-pot synthesis of 4-bromotetrahydropyrans in a highly diastereoselective manner via the alkynylation followed by Prins cyclisation is described. The method employs aldehydes and allyl bromide as reactants, with a Zn/ZnBr2 catalytic system in CH2Cl2. A variety of 2,6-disubstituted 4-bromotetrahydropyran derivatives were obtained in good yields.
Citation: SynOpen 2022; 06: 263-269
PubDate: 2022-10-19T13:57:23+01:00
DOI: 10.1055/s-0042-1751374
Issue No: Vol. 06, No. 04 (2022)
- Recent Progress on the [3+2] Cycloaddition Route for the Synthesis of
All-Carbon Quaternary Stereocentres
Authors: Deepthi; Ani, Mohan, Maneesh, Balachandran, Meenakshy C.
Pages: 270 - 285
Abstract: Construction of all-carbon quaternary centres is an important task in organic synthesis. In spite of the challenges associated with Csp3–Csp3 bond construction in a sterically constrained environment, significant advances have been made in this area. Among the latter, both catalytic and noncatalytic [3+2] cycloaddition approaches have gained wide attention recently. This short review summarizes the [3+2] cycloaddition reactions reported during the period 2016–2022 for the synthesis of molecules possessing one or more all-carbon quaternary stereocentres.
Citation: SynOpen 2022; 06: 270-285
PubDate: 2022-10-20T13:03:47+01:00
DOI: 10.1055/a-1947-3351
Issue No: Vol. 06, No. 04 (2022)
- Transition-Metal-Catalyzed Remote C–H Bond Functionalization of
Cyclic Amines
Authors: Chen; Weijie, Yang, Xiaoyu, Cao, Xi
Pages: 286 - 305
Abstract: C–H bond functionalization is one of the most effective strategies for the rapid synthesis of cyclic amines containing substituents on the ring, which are core structures of many bioactive molecules. However, it is much more challenging to perform this strategy on remote C–H bonds compared to the α-C–H bonds of cyclic amines. This graphical review aims to provide a concise overview on transition-metal-catalyzed methods for the remote C–H bond functionalization of cyclic amines. Examples are categorized and demonstrated according to mechanistic pathways that initiate the reactions of cyclic amine substrates. Where relevant, selected substrate scope and detailed reaction mechanisms are given.
Citation: SynOpen 2022; 06: 286-305
PubDate: 2022-10-24T14:32:37+01:00
DOI: 10.1055/a-1929-9789
Issue No: Vol. 06, No. 04 (2022)
- Practical, Multigram Preparation of Synthetically Useful, Enantiomerically
Pure Building-Blocks from Quinic Acid
Authors: Tan; Shen, Lan, Ping, Banwell, Martin G., White, Lorenzo V.
Pages: 306 - 311
Abstract: The naturally abundant, enantiomerically pure cyclitol quinic acid has been converted into a synthetically useful enone in nearly quantitative yield using the operationally straightforward and reproducible protocols reported herein. The latter compound, which was obtained in multigram quantities, engages in a diastereoselective 1,2-addition reaction with a hydrazone-based nucleophile. Furthermore, a readily derived α-iodoenone participates in both cross-coupling and α,β-annulation reactions. The results reported here emphasize that the now practically accessible cyclohexenones are useful, enantiomerically pure building blocks for organic synthesis.
Citation: SynOpen 2022; 06: 306-311
PubDate: 2022-11-21T14:36:18+0100
DOI: 10.1055/a-1952-4557
Issue No: Vol. 06, No. 04 (2022)
- Stereoselective Synthesis of Euscapholide and Tetraketide via Prins
Cyclisation and Ring-Closing Metathesis
Authors: Biradar; Dhanraj O., Mane, Yogesh D., Subba Reddy, Basi V.
Pages: 312 - 318
Abstract: A concise and diastereoselective total synthesis of tetraketide and euscapholide is described in ten steps in 10.6% overall yield from acetaldehyde and (S)-pent-4-ene-1,2-diol. Jacobsen hydrolytic kinetic resolution, Prins cyclization, ring-closing metathesis and oxa-Michael addition reactions are the key steps involved in the synthesis.
Citation: SynOpen 2022; 06: 312-318
PubDate: 2022-11-24T09:35:54+0100
DOI: 10.1055/s-0042-1751381
Issue No: Vol. 06, No. 04 (2022)
- Synthesis of α-Sulfoximino Tetrazoles via Azido-Ugi Four-Component
Reaction
Authors: Jesin; C. P. Irfana, Kataria, Ramesh, Nandi, Ganesh Chandra
Pages: 319 - 328
Abstract: The sulfoximine-based tetrazoles have been synthesized via azido-Ugi four-component reactions of sulfoximines, isocyanides, aldehydes, and TMS-azide in MeOH at 70 °C in the presence of InCl3. Replacement of sulfoximines with sulfonimidamides (SIA) has delivered the corresponding SIA-based tetrazole. Interestingly, SIA also acts as a surrogate amine to furnish the corresponding aminotetrazole as a by-product.
Citation: SynOpen 2022; 06: 319-328
PubDate: 2022-12-12T11:02:37+0100
DOI: 10.1055/a-1981-9151
Issue No: Vol. 06, No. 04 (2022)
- A Green, Scalable, and Catalyst-Free One-Minute Synthesis of Quinoxalines
Authors: Elumalai; Vijayaragavan, Hansen, Jørn H.
Abstract: A highly efficient and catalyst-free protocol is reported for the synthesis of quinoxalines via the classical cyclocondensation reaction between aryldiamines and dicarbonyl compounds. Remarkably simple and green reaction conditions employing methanol as solvent afforded medium to excellent yield of quinoxalines after only one-minute reaction time at ambient temperature. The conditions allow at least 10 gram scale synthesis of quinoxalines and should be a preferred starting point for optimization and method of choice for applications in the synthetic community.
Citation: SynOpen 2022; :
PubDate: 2021-02-10T00:00:00+0100
DOI: 10.1055/s-0040-1706021
- Sodium Persulfate (Na2S2O8)
SynOpen 2022;
DOI: 10.1055/a-1656-5714
[...]
Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany
Artikel in Thieme eJournals:
Inhaltsverzeichnis Abstract open access Volltext
SynOpen 2022; : 2021-10-06T00:00:00+01:00
Issue No: Vol.
Sustainab, No. Sustainable Transformations (2021)
- An Efficient and Practical Chemoenzymatic Route to
(3R,3aR,6R,6aR)-Hexahydrofuro[3,2-b]furan-6-amino-3-ol (6-Aminoisomannide)
from Renewable Sources
Authors: Zullo; Valerio, Petri, Antonella, Iuliano, Anna
Abstract: The synthesis of 6-aminoisomannide is easily achieved starting from the renewable, inexpensive, and commercially available isosorbide in 66% overall yield. A biocatalyzed highly regioselective acetylation of the 3-endo hydroxyl group of isosorbide was followed by the stereospecific interconversion of the 6-exo hydroxyl group into an azido group, through reaction with trifluoromethanesulfonic anhydride, followed by nucleophilic displacement of the triflate group by sodium azide. Finally, reduction of the azido group and deacetylation of the 3-hydroxy group were performed in one pot using LiAlH4.
Citation: SynOpen 2022; :
PubDate: 2021-07-06T00:00:00+01:00
DOI: 10.1055/a-1532-5825
Issue No: Vol.
Sustainab, No. Sustainable Transformations (2021)
- Visible-Light-Mediated Photocatalytic Oxidative C–C Bond Cleavage of
Geminal Diazides: An Approach to Oxamates
Authors: Katta; Narenderreddy, Murugan, Arumugavel, Sharma, Sonika, Sharada, Duddu S.
Abstract: Photoredox catalysis has received great attention in both academia and industry and remarkable progress has been made over the past decade. Now, it has been shown that a visible-light-mediated oxidative C–C bond cleavage of geminal diazides can be induced by organic dye catalysis for the synthesis of oxamates. A mechanistic study, confirmed by control experiments, indicates that this proceeds through single-electron transfer (SET). This methodology can be applied to convert a wide array of geminal diazides into oxamates.
Citation: SynOpen 2022; :
PubDate: 2021-06-17T00:00:00+01:00
DOI: 10.1055/s-0040-1706048
Issue No: Vol.
Sustainab, No. Sustainable Transformations (2021)
- Synthesis of Spiro Pyrazolone-Oxindole and Bicyclic Pyrazolone Derivatives
via Solvent-Dependent Regioselective Aza-1,4/1,6-Michael and
Intramolecular Cycloaddition under Catalyst-Free Conditions
Authors: Sathish; Kota, Nagaraju, Sakkani, Kashinath, Dhurke
Abstract: A solvent-dependent, highly regioselective [3+2]-cycloaddition reaction of isoxazole-styrenes and azomethine imines under catalyst-free conditions is reported, furnishing a library of pyrazolone–spirooxindole hybrids. Good regioselectivity for the isomeric structures was achieved by the reaction of isoxazole-styrene and azomethine imine in different solvents and temperatures. The developed method was extended for the synthesis of tri-substituted dinitrogen-fused pyrazolones by using a 1,6-Michael addition reaction. Furthermore, the isoxazole moiety was converted into a carboxylic acid as a model study via ring opening.
Citation: SynOpen 2022; :
PubDate: 2021-05-20T00:00:00+01:00
DOI: 10.1055/a-1480-9837
Issue No: Vol.
Sustainab, No. Sustainable Transformations (2021)
- A Stable and Safe Form of Iodine Azide: Polymer-Bound Bisazidoiodate(I)
SynOpen 2022;
DOI: 10.1055/a-1480-8983
[...]
Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany
Artikel in Thieme eJournals:
Inhaltsverzeichnis Abstract open access Volltext
SynOpen 2022; : 2021-05-04T00:00:00+01:00
Issue No: Vol.
Sustainab, No. Sustainable Transformations (2021)
- Clean One-Pot Multicomponent Synthesis of Pyrans Using a Green and
Magnetically Recyclable Heterogeneous Nanocatalyst
Authors: Ghassemi; Mina, Maleki, Ali
Abstract: Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde, and a β-ketoester in ethanol at room temperature. The nanoparticles were characterized by FT-IR, EDX, SEM, TGA, and DTG analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, using a green solvent under environmentally friendly reaction conditions, ease of catalyst recovery and recyclability, no need for column chromatography and good to excellent yields are advantages of this protocol.
Citation: SynOpen 2022; :
PubDate: 2021-04-12T00:00:00+01:00
DOI: 10.1055/a-1469-6721
Issue No: Vol.
Sustainab, No. Sustainable Transformations (2021)
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