Synthesis of a Triphenylphosphinimide-Substituted Silirane as a "Masked" Acyclic Silylene.

Phosphinimides are long known as useful ligands in transition metal chemistry, but examples of these in low-valent silicon chemistry are rather rare. Hence, in this work, we report on the implementation of a triphenylphosphinimide moiety as a ligand of a novel silylene that is trapped as a silirane with cyclohexene. By performing activation reactions with B( p -Tol) 3 , HSiEt 3 , N 2 O, and NH 3 , we demonstrate that the silirane exhibits a silylene-like behavior, making it a "masked" silylene. Furthermore, we treated the silirane with ethylene, propylene, and trans -butene, which led to an olefin exchange. In the case of ethylene and propylene, an additional insertion of the olefin into the silicon-silicon bonds of the respective siliranes could be achieved. As the insertion of trans -butene was not feasible, we surmise that the scope of this reactivity is restricted by the steric demand of the olefin.