1-Trimethylsilylphosphirane as a ligand and as a stable masked reagent for phosphirane

Abstract

1-Trimethylsilylphosphirane, C₂H₄PSiMe₃, has been prepared on a multi gram scale from P(SiMe₃)₃via ClCH₂CH₂P(SiMe₃)₂. C₂H₄PSiMe₃ is readily susceptible to protonolysis forming the thermally unstable parent phosphirane, C₂H₄PH, in good yields. Reaction of C₂H₄PSiMe₃ with fac-M (CO)₃(CH₃CN)₃ (M = Cr, Mo) or [Fe(η⁵-C₅H₅)(η⁶-C₆H₆)](PF₆) give rise to fac-M(CO)₃(C₂H₄PSiMe₃)₃ and [Fe(η⁵-C₅H₅)(C₂H₄PSiMe₃)₃](PF₆) respectively. Protonolysis of the free or coordinated 1-trimethylsilylphosphirane readily causes P–Si cleavage to give rise to the parent C₂H₄PH or the respective complexes, fac-M(CO)₃(C₂H₄PH)₃ and fac-[Fe(η⁵-C₅H₅)(C₂H₄PH)₃](PF₆) in situ. All new complexes are characterised by analytical and spectroscopic methods and the X-ray crystal structures of fac-Cr(CO)₃(C₂H₄PSiMe₃)₃ and fac-Mo(CO)₃(C₂H₄PH)₃ have also been determined.