Chiral oxamide–phosphine–palladium catalyzed highly asymmetric allylic amination: carbonyl assistance for high regio- and enantiocontrols

Abstract

A new type of chiral oxamide–phosphine (COAP) ligand was developed for the palladium-catalyzed asymmetric allylic amination of vinyl benzoxazinones with alkylamines, affording a variety of enantiomerically enriched 2-(1-aminoallyl)aniline derivatives in high yields (up to 92%) with high enantioselectivities (up to 94% ee). Mechanistic studies via control experiments and DFT calculations suggested that carbonyl coordination to palladium, although distinct from that of the phosphine moiety in the same chiral ligand, is crucial for the regio- and enantioselective control of this transformation. COAP ligands possess some salient features of modular structure, fine stereoelectronic tunability and facile synthesis, coupled with the strategic incorporation of coordinatively distinct phosphine and carbonyl moieties into the same skeleton.