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†
Abstract
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.