Catalytic asymmetric [3+2] annulation of allylsilanes with isatins: Synthesis of spirooxindoles

Abstract

Silyl-inspired spirocycle: The title reaction is the first example of a catalytic asymmetric [3+2] annulation reaction with allylsilanes. The annulation reaction utilizes a chiral ScCl 2(SbF 6)/L catalyst and TMSCl as a promoter to afford spirooxindoles in excellent enantioselectivity at room temperature. The Si-C bond can be oxidized to deliver hydroxy-substituted spirooxindoles. TMS=trimethylsilyl. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.