Nickel-catalyzed ring-opening alkylative coupling of enone with methylenecyclopropane in the presence of triethylborane.

Nickel-catalyzed alkylative coupling of an enone or enal with methylenecyclopropane in the presence of triethylborane was achieved via stereospecific proximal C-C bond cleavage of methylenecyclopropane. With the use of methylenecyclopropane possessing an acyclic alkyl substituent, this reaction was also accompanied by the β-hydrogen elimination.