Multiple Hydrogen‐Bonding Catalysts Enhance the Asymmetric Cyanation of Ketimines and Aldimines

Abstract

AbstractA highly enantioselective cyanation of imines (up to >99 % ee) has been developed using well‐designed C2‐symmetric hydrogen bonding catalysts. The catalytic strategy was characterized with low catalyst loading (0.1–1 mol %), easily accessible catalysts with diverse functional groups, and catalytic base additives. A wide range of imines, including the challenging N‐Boc and N‐Cbz protected ketimines and aldimines, as well as fluoroalkylated ketimines, were investigated under mild conditions to afford the products with good to excellent yields (up to 99 % yield) and high enantioselectivity (up to >99 % ee). Control experiments revealed that the multiple hydrogen bonding catalysts enhanced the reactivity and enantioselectivity of the Strecker reaction initiated by the base.