Phosphorus Silicon Compounds from the Reduction of MesP(H)SiCl2Ph/Carbene with and without Metal

Abstract

MesP(H)SiCl2Ph (Mes = 2,4,6-Me3C6H2) (7) with a reactive Si–Cl and P–H bond can easily be reduced by KC8 or alternatively by a carbene to give remarkable phosphorus silicon compounds. 7 is readily synthesized from the reaction of MesPH2 sequentially with nBuLi and PhSiCl3 in a 1:1:1 ratio. KC8 reduction of MesP(H)SiCl2Ph (7) in the presence of cyclic alkyl(amino) carbene (cAACMe) gives (MesPH)3SiPh (8) and cAAC-stabilized Si2Ph2 (9). In addition, 9 might also be formed by the reduction of PhSiCl3 using KC8 in the presence of cAACMe. Treatment of MesP(H)SiCl2Ph (7) with IiPr2Me2 (IiPr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) in a molar ratio of 1:2 results in HCl elimination as IiPr2Me2·HCl. The second equivalent of IiPr2Me2 was used to yield well-defined phosphasilene (10) containing a Ph(Cl)Si=PMes moiety. This unit will gain much application in ligand design because the chlorine atom can readily be replaced by other substituents.