Acylation of nitronates affords α-acyloxyoxime derivatives via an umpolung functionalization of the α-position. This transformation involves generation of hitherto unknown N-acyloxy, N-oxyenamines and their fast [3,3]-sigmatropic rearrangement driven by the cleavage of the weak N-O bond. The reaction has a broad scope, and it is regioselective in the case of nitronates possessing nonsymmetrically substituted α-positions. Application to the formal total synthesis of clausenamide and cis-clausenamide is presented.
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http://dx.doi.org/10.1021/acs.joc.8b01652 | DOI Listing |
Molecules
October 2022
College of Pharmacy and Innovative Drug Center, Duksung Women's University, 33 Samyangro 144-gil, Dobong-gu, Seoul 01369, Korea.
The syntheses of novel 1-acyloxyindole compounds and the investigations on reaction pathways are presented. Nitro ketoester substrate , obtained in a two-step synthetic process, underwent reduction, intramolecular addition, nucleophilic 1,5-addition, and acylation to afford 1-acyloxyindoles in one pot. Based on the systematic studies, we established the optimized reaction conditions for focusing on the final acylation step of the intermediate 1-hydroxyindole .
View Article and Find Full Text PDFMolecules
August 2020
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia.
Angew Chem Int Ed Engl
February 2020
EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK.
The importance of 1,5-O⋅⋅⋅chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N-acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5-O⋅⋅⋅Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal [4+2] cycloadditions.
View Article and Find Full Text PDFInt J Syst Evol Microbiol
May 2019
1OMICS Laboratory, Department of Biotechnology, University of North Bengal, Siliguri 734 013, West Bengal, India.
A Gram-stain-positive, spore-forming bacterium, EAG3, capable of growing on 3-nitropropionic acid as the sole source of carbon, nitrogen and energy, was isolated from the anterior gut of an earthworm (Eisenia fetida) reared at the Centre of Floriculture and Agribusiness Management of the University of North Bengal at Siliguri (26.7072° N, 88.3558° E), West Bengal, India.
View Article and Find Full Text PDFJ Org Chem
September 2018
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , Leninsky prospect 47 , 119991 , Moscow , Russian Federation.
Acylation of nitronates affords α-acyloxyoxime derivatives via an umpolung functionalization of the α-position. This transformation involves generation of hitherto unknown N-acyloxy, N-oxyenamines and their fast [3,3]-sigmatropic rearrangement driven by the cleavage of the weak N-O bond. The reaction has a broad scope, and it is regioselective in the case of nitronates possessing nonsymmetrically substituted α-positions.
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