Organocatalytic Atroposelective Construction of Axially Chiral N-Aryl Benzimidazoles Involving Carbon-Carbon Bond Cleavage.

Axially chiral compounds widely occur in natural products, biologically active molecules, ligands, and catalysts, and their efficient and enantioselective synthesis is highly desirable. Herein, we report a novel method for the atroposelective construction of axially chiral N-aryl benzimidazoles with chiral phosphoric acid as the organocatalyst via reaction of N1-(aryl)benzene-1,2-diamines with multicarbonyl compounds. The present method provided the target products in high yields (up to 89%) with excellent enantioselectivity (up to 98% ee).