Enantioselective Construction of Spirocyclic Oxindolic Cyclopentanes by Palladium-Catalyzed Trimethylenemethane-[3+2]-Cycloaddition
作者:Barry M. Trost、Nicolai Cramer、Steven M. Silverman
DOI:10.1021/ja075335w
日期:2007.10.1
The palladium catalyzed [3+2] trimethylenemethane (TMM) cycloaddition is an efficient method for the construction of cyclopentanes. Herein, we report a catalytic asymmetric protocol for the synthesis of spirocyclic oxindolic cyclopentanes in excellent yields and enantioselectivities, allowing for the first time the construction of up to three adjacent stereogenic centers. In this process, the chiral
Vinylogy: Advances in asymmetric catalysis using the bifunctional cinchona alkaloid/thioureas enabled an umpolung of the classical Cβ reactivity of 3‐alkylidene oxindoles, thus allowing the development of the first and sole example of a direct, organocatalytic asymmetric vinylogous Michael (AVM) reaction with nitroolefins.