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(PPh3)(4) was demonstrated to be the optimal catalyst, allowing for a variety of carbon carbon pi-bond insertion reactions. Depending on the nature of the carbon carbon pi bond, the insertion reaction proceeded with either direct insertion into the carbon(sp(2)) 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.