A metal–amide dependent, catalytic C–H functionalisation of triphenylphosphonium methylide

Abstract

We report the [Y{N(SiMe₃)₂}₃] catalysed dehydrocoupling of triphenylphosphonium methylide with phenylsilane to form the silylated ylide Ph₃PCHSiH₂Ph. Attempts to catalyse this reaction with the related group 2 hexamethyldisilazide base [Ca{N(SiMe₃)₂}₂] led to the catalytic formation of the phosphine Ph₂PCHSiH₂Ph along with Ph₂PMe in low selectivity, while group 1 bases [M{N(SiMe₃)₂}] (M = Li, Na, K) proved ineffective for both transformations. The stoichiometric reactions of Ph₃PCH₂ with [M{N(SiMe₃)₂}_n] have been investigated and allowed the isolation and characterisation of a cyclometallated phosphonium methylide complex of yttrium.