Organocatalytic and Electrophilic Approach to Oxindoles with C3-Quaternary Stereocenters

A Lewis base-catalyzed asymmetric allylic alkylation of Morita-Baylis-Hillman carbonates derived from isatins has been investigated, which provides an electrophilic pathway to access oxindoles bearing C3-quaternary stereocenters. Excellent diastereoselectivity and high enantioselectivity have been obtained in the vinylogous functionalization of alpha,alpha-dicyanoolefin nucleophiles, giving multifunctional products with vicinal quaternary and tertiary chiral carbon centers.