Catalytic cyclopropanation reactions with α-silyl-, germanyl- and stannyl carbenes generated from cyclopropenes.

Silylcyclopropenes are employed as precursors of α-silyl vinyl carbenes and trapped with alkenes. Cyclopropylsilanes were obtained in good yields with ample scope and complete regio- and diastereoselectivity. Stereoretentive protodesilylations enabled access to cis -1,2-disubstituted cyclopropanes. Cyclopropylstannanes and -germanes can also be prepared from the corresponding cyclopropenes.