Ene reactions of (Z)-1,4-bis(trimethylsilyl)buta-1,2,3-triene with α,β-unsaturated carbonyl compounds

Carbon–carbon bond formation reactions of a silyl-substituted [3]cumulene, (Z)-1,4-bis(trimethylsilyl)buta-1,2,3-triene (1), with α,β-unsaturated carbonyl compounds in the presence of Lewis acids are presented. The reactions gave 1,3-enyne compounds bearing a carbonyl moiety, and the silyl groups of 1 were maintained in the products. The reaction of 1,4-dideuterated 1-d2 suggested that the C–C bond formation proceeds by an ene reaction mechanism.