ORGANOSILICON CHEMISTRY XXX. HOMOGENEOUS CATALYSIS BY IRIDIUM(I) COMPLEXES OF THE REACTION BETWEEN SILANES AND ALCOHOLS OR DIDEUTERIUM

Article abstract of DOI:10.1016/S0022-328X(00)81223-1

The complexes IrX(CO)L2, IrCl(N2)(PPh3)2, 2, and IrClL2 (X = halide, L = tertiary phosphine or arsine) are excellent catalysts for the reactions of HSiR3 (R = Ph, Et, OEt) with R'OH (R' = Et, Me).With IrX(CO)L2 the reaction is inhibited by an excess of HSiR3 and by the product, H2.The proposed mechanism involves intermediate formation of ClSiR3 by elimination from the silyl complex IrHX(SiR3)(CO)L2.The iridium(I) complex IrH(CO)L2, also formed in this step, reacts with HCl in the catalytic cycle or with H2 or HSiR3 in the inhibition reactions.The exchange reaction of HSiR3 (R = OEt, Et) with D2 is catalysed by IrCl(CO)(PPh3)2 or IrH3(CO)(PPh3)2, and probably has a similar mechanism.Catalysis of the HSiR3-R'OH reaction by the other iridium(I) complexes probably involves direct attack by the alcohol on the coordinated silyl group of the intermediate IrHCl(SiR3)L2.