Stable Axially Chiral Cyclohexylidenes from Catalytic Asymmetric Knoevenagel Condensation

Abstract

AbstractAxially chiral cycloalkylidenes are interesting but less developed axially chiral molecules. Here, a bispidine‐based chiral amine catalytic system was developed to promote efficiently the asymmetric Knoevenagel condensation of N‐protected oxindoles and benzofuranones with 4‐substituted cyclohexanones. A variety of alkylidenecycloalkanes with stable axial chirality were obtained in good yields and fairly good er (enantiomeric ratio). Based on the absolute configuration determination of product and DFT calculations, a possible mechanism of stereoselective induction was proposed.