Synergistic Bimetallic Ni/Ag and Ni/Cu Catalysis for Regioselective gamma,delta-Diarylation of Alkenyl Ketimines: Addressing beta-H Elimination by in Situ Generation of Cationic Ni(II) Catalysts

We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective ykdiarylation of unactivated alkenes in simple ketimines with aryl halides and arylzinc reagents. The bimetallic synergy, which generates cationic Ni(II) species during reaction, promotes migratory insertion and transmetalation steps and suppresses beta-H elimination and cross coupling, the major side reactions that cause serious problems during alkene difunctionalization. This diarylation reaction proceeds at remote locations to imines to afford, after simple H+ workup, diversely substituted gamma,delta-diaryl ketones that are otherwise difficult to access readily with existing methods.