Synthesis of multiply substituted alkylidene silacyclohexadiene derivatives via palladium-catalyzed insertion of alkynes into alkylidene silacyclobutenes.

Palladium-catalyzed insertion of activated alkynes into silacyclobutene derivatives proceeded smoothly to afford exo-alkylidenesilacyclohexadiene derivatives of unique structure with diversified conjugation systems in high isolated yields. Interesting regioselectivity of insertion, which afforded only one regioisomer or a mixture of two or more regioisomers, was also observed.