Isocyanide-promoted ylidene transfer to phosphorus: Rearrangement in the first-generation Grubbs complex

Carbon monoxide or an aryl isocyanide promotes a benzylidene carbene transfer from ruthenium to tricyclohexylphosphine in the first-generation Grubbs carbene complex. The resulting ruthenium(II) complexes have been isolated and structurally characterized by X-ray crystal structure analysis; a probable mechanism for the ligand-promoted transformation is also discussed.