Palladium- and nickel-catalyzed carbon-carbon bond insertion reactions with alkylidenesilacyclopropanes

Palladium and nickel catalysts promoted highly selective carbon-carbon bond insertion reactions with di-tert-butyl-alkylidenesilacyclopropanes. Pd(PPh ₃)₄ was demonstrated to be the optimal catalyst, allowing for a variety of carbon-carbon π-bond insertion reactions. Depending on the nature of the carbon-carbon π bond, the insertion reaction proceeded with either direct insertion into the carbon(sp²)-silicon bond or allylic transposition. Ring-substituted alkylidenesilacyclopropanes required a nickel catalyst to afford insertion products. Using Ni(cod)₂ as the carbon-carbon bond insertion catalyst, new double alkyne insertion products and alkene isomerization products were observed.