Ni-Catalyzed C-C Bond Formation with α,β-Unsaturated Carbonyl Compounds and Alkynes

This account reviews the Ni-catalyzed C-C bond-forming reactions of alpha,beta-unsaturated carbonyl compounds with alkynes, affording the corresponding trienes, dienes, arenes, bicyclohexenes, and 4H-pyrans. The nickelacycles formed by the oxidative cyclization of an alpha,beta-unsaturated carbonyl compound with an alkyne catalyzed by a Ni(0) complex play important roles as the active intermediates in the reactions. The reactions reported in this review are mechanistically new, and provide new methods for the construction of molecular frameworks using readily available alpha,beta-unsaturated carbonyl compounds and alkynes.