Lewis-Base-Catalyzed Asymmetric Allylation of Isatins with Allyltrichlorosilane

Herein we report the enantioselective synthesis of 3-allyl-3-hydroxyoxindoles, a core scaffold in a wide range of bioactive molecules, using a Lewis-base catalyst and readily abundant and inexpensive allyltrichlorosilane. This transition-metal-free protocol employs relatively low catalyst loadings of a privileged bispyrrolidine-type scaffold to achieve high yields and enantioselectivities (up to 98% yield and 98:2 er). The total syntheses of the natural products (-)-flustraminol B and (-)-chimonamidine were also successfully carried out using our newly developed method as a key step, highlighting the potential of this method for the efficient and precise synthesis of complex natural products.