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.