Catalytic asymmetric [3+2] cycloaddition of aromatic aldehydes with oxiranes by C-C bond cleavage of epoxides: highly efficient synthesis of chiral 1,3-dioxolanes

摘要

A novel and efficient N,N'-dioxide-Gd(Ⅲ) complex was developed for the highly diastereo- and enantioselective [3+2] cycloaddition of aryl oxiranyl diketones and aldehydes via C-C bond cleavage of oxiranes. The corresponding chiral 1,3-dioxolanes were obtained in excellent yields (up to 99%) with high diastereoselectivities (＞95:5 dr) and enantioselectivities (up to 91% ee). Moreover, a possible transition model was proposed to explain the origin of the asymmetric induction.