 Formation of the new carbon-carbon bond is at the γ position of allyl silanes and the β position of vinylsilanes.The robustness of silanes makes them amenable to use in synthesis; however, because silicon is less electropositive than other metals employed in electrophilic additions, stronger electrophiles are required.The carbon-silicon bond is highly electron-releasing and can stabilize a positive charge in the β position through hyperconjugation.