Nickel-Catalyzed Tandem Coupling of alpha,beta-Enones, Alkynes, and Alkynyltins for the Regio- and Stereoselective Synthesis of Conjugated Enynes.

The nickel-catalyzed reaction of alpha,beta-enones 2 with alkynes 1, alkynyltins 6, and Me(3)SiCl was carried out by the successive construction of two carbon-carbon bonds to give enol silyl ethers 5, which were then hydrolyzed to conjugated enynes 7, with high regio- and stereoselectivities (isomeric purities: 92-98%).