Skeletal Rearrangements Involving Cyclopropyl- and Alkene-Stabilized Silylium Ions

This Account summarizes the fascinating chemistry of cyclopropyl-stabilized silylium ions, which are readily available from vinyl-cyclopropanes (VCPs). Depending on the nucleophilic partner, these reactive intermediates undergo direct ring opening or ring expansion to nonclassical alkene-stabilized silylium ions. The latter can also be accessed by gold as well as proton electrophiles from silicon compounds containing unsaturated C-C bonds. All these reaction cascades can be terminated by C-H or C-C as well as Si-O bond formation. From this, a clearer picture of the versatility of these rather complex chemistries emerges.

Automated summary

This Account summarizes the fascinating chemistry of cyclopropyl-stabilized silylium ions, which can be readily obtained from vinyl-cyclopropanes (VCPs). Depending on the nucleophilic partner, these reactive intermediates undergo direct ring opening or ring expansion, leading to the formation of nonclassical alkene-stabilized silylium ions. The latter can also be obtained by gold and proton electrophiles from silicon compounds containing unsaturated C-C bonds. These reaction cascades can be terminated by the formation of C-H or C-C as well as Si-O bonds, revealing the versatility of these complex reactions.