A new, efficient method for direct α-alkenylation of β-dicarbonyl compounds and phenols using alkenyltriarylbismuthonium salts

Direct alpha-alkenylation of beta-keto esters, beta-diketone, and phenols with alkenyltriarylbismuthonium salts proceeded smoothly in the presence of 1,1,3,3-tetramethylguanidine to afford the corresponding alpha-alkenylated carbonyl compounds (beta,gamma-unsaturated carbonyl compounds) in good yields. The high leaving ability of the triarylbismuthonio group is a key driving force to achieve the C-C bond formation at the vinylic carbon under mild conditions.