A1 Refereed original research article in a scientific journal
Switchable Access to Different Spirocyclopentane Oxindoles by N-Heterocyclic Carbene Catalyzed Reactions of Isatin-Derived Enals and N-Sulfonyl Ketimines
Authors: Wang L, Li S, Blumel M, Puttreddy R, Peuronen A, Rissanen K, Enders D
Publisher: WILEY-V C H VERLAG GMBH
Publication year: 2017
Journal: Angewandte Chemie International Edition
Journal name in source: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
Journal acronym: ANGEW CHEM INT EDIT
Volume: 56
Issue: 29
First page : 8516
Last page: 8521
Number of pages: 6
ISSN: 1433-7851
DOI: https://doi.org/10.1002/anie.201704210(external)
Abstract
A novel NHC-catalyzed annulation protocol for the asymmetric synthesis of biologically important beta-lactam fused spirocyclopentane oxindoles with four contiguous stereocenters, including two quaternary carbon centers, was developed. Alternatively, spirocyclopentane oxindoles containing an enaminone moiety can be achieved using the same starting materials, isatin-derived enals, and N-sulfonyl ketimines, in the presence of a slightly different NHC catalytic system. This switchable annulation strategy enables the selective assembly of both heterocyclic scaffolds with good yields and excellent enantioselectivities for a broad range of substrates.
A novel NHC-catalyzed annulation protocol for the asymmetric synthesis of biologically important beta-lactam fused spirocyclopentane oxindoles with four contiguous stereocenters, including two quaternary carbon centers, was developed. Alternatively, spirocyclopentane oxindoles containing an enaminone moiety can be achieved using the same starting materials, isatin-derived enals, and N-sulfonyl ketimines, in the presence of a slightly different NHC catalytic system. This switchable annulation strategy enables the selective assembly of both heterocyclic scaffolds with good yields and excellent enantioselectivities for a broad range of substrates.