Enantioselective and Regioselective Copper-Catalyzed Borocyanation of 1-Aryl-1,3-Butadienes

A multicomponent copper-catalyzed enantio- and regioselective borocyanation of 1-aryl-1,3-butadienes has been developed. The method provides access to functionalized allylic nitriles in up to 90% yield and 94% ee and thus overcomes some of the long-standing problems associated with the enantioselective insertion of cyano groups into unsaturated organic molecules. Both boron and cyano functionalities can be used as handles for selective manipulation.