Organocatalytic Enantioselective Construction of Chiral Azepine Skeleton Bearing Multiple‐Stereogenic Elements

Abstract

Enantioselective construction of molecules bearing multiple stereogenic elements is increasingly related to the synthesis of enantiopure natural products,p harmaceuticals, and functional materials.H owever,a tom-economical and enantioselective approaches to install multiple stereogenic elements in as mall molecular template by limited chemical transformation remain challenging.W ed escribe an organocatalytic enantioselective method for the preparation of polychiral molecules bearing four types of stereogenic elements in fused azepines via vinylidene ortho-quinone methide (VQM)mediated intramolecular electrophilic aromatic substitution. This method was proved robust with awide range of substrate scope (46-92 %y ield), with excellent diastereoselectivity (> 20:1 dr) and enantioselectivity achieved (up to 97 %e e). Optical properties and Ru 3+ -induced fluorescence responses of these compounds suggest their potential applications in optoelectronic materials and heavy metal ion detection.