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

• Published in: Journal of the American Chemical Society Vol. 140; no. 46; pp. 15586 - 15590
• Main Authors: Basnet, Prakash, KC, Shekhar, Dhungana, Roshan K, Shrestha, Bijay, Boyle, Timothy J, Giri, Ramesh
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 21.11.2018; Amer Chemical Soc; American Chemical Society (ACS)
• Subjects: Chemistry; Chemistry, Multidisciplinary; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Physical Sciences; Science & Technology; PALLADIUM; 3-COMPONENT COUPLING REACTION; UNACTIVATED OLEFINS; DICARBOFUNCTIONALIZATION; INTRAMOLECULAR HECK REACTIONS; COPPER(I) SALTS; TERMINAL ALKENES; CYCLIZATION; ALKYL-HALIDES; INTERMOLECULAR CYANOTRIFLUOROMETHYLATION
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.8b09401

We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective γ,δ-diarylation 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 β-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 γ,δ-diaryl ketones that are otherwise difficult to access readily with existing methods.