Enantioselective Copper-Catalyzed\nBorylative Amidation\nof Allenes

An\napproach for the copper-catalyzed synthesis of enantioenriched\namides bearing an α-stereogenic center is disclosed. This method\ninvolves the addition of an allyl copper species to an isocyanate\nand allows access to α-substituted chiral amides in high yields\nand high-to-excellent enantioselectivities. The utility of α-vinyl\nβ-boryl amides in synthesis is highlighted by the diversification\nof products to afford highly useful scaffolds. DFT calculations reveal\nthat the catalyst preferentially coordinates to the oxygen of the\nisocyanate. Enantiocontrol arises from the steric repulsion between\nthe boryl group and the stereodirecting phenyl of the chiral ligand.