The synthesis of an enantiopure planar-chiral Lewis acid complex via kinetic resolution and its application in stereoselective additions to imines

This report describes the synthesis and an application of a new planar-chiral Lewis acid based on a 1,2-azaborolyl framework. The enantiopure complex is generated through an intriguing kinetic resolution by a chiral nucleophile. Imines bind in excellent yield to the planar-chiral 1,2-azaborolyl, furnishing crystallographically characterizable adducts that adopt the conformation that had been anticipated on the basis of steric considerations. Nucleophiles add with high stereoselectivity to these complexes, with the predicted sense of asymmetric induction.