A versatile difluorovinylation method: Cross-coupling reactions of the 2,2-difluorovinylzinc-TMEDA complex with alkenyl, alkynyl, allyl, and benzyl halides

A thermally stable 2,2-difluorovinylzinc-TMEDA complex was prepared via a deprotonation-transmetallation sequence starting from commercially available 1,1-difluoroethylene. The complex thus formed was successfully applied to transition metal-catalyzed cross-coupling reactions with a wide range of organic halides, which led to the syntheses of 2,2-difluorovinyl compounds. On treatment with the difluorovinylzinc-TMEDA complex in the presence of an appropriate palladium or copper catalyst, alkenyl, alkynyl, allyl, and benzyl halides effectively underwent difluorovinylation to afford 1,1-difluoro-1,3-dienes, 1,1-difluoro-1,3-enynes, 1,1-difluoro-1,4-dienes, and (3,3-difluoroallyl)arenes, respectively. (C) 2014 Elsevier B.V. All rights reserved.