Highly selective nickel-catalyzed three-component coupling of alkynes with enones and alkenyl boronic acids: a novel route to substituted 1,3-dienes.

A highly regio- and stereoselective nickel-catalyzed three-component coupling of alkynes with enones and alkenyl boronic acids to afford highly substituted 1,3-dienes is described. The reaction can also be extended to cyclization of enynes with coupling to alkenyl boronic acids. A possible reaction mechanism involving a five-membered nickelacycle as a key intermediate is proposed.