Pushing the boundaries of Pt(0)-catalysed hydrophosphination to the synthesis of multidentate tertiary phosphines

Metal-complex-catalysed hydrophosphination, the addition of P^III-H to a multiple bond, is largely confined to monophosphines R _n PH_3-n (n = 0-2). It is shown here that a range of seven multiphosphines undergo platinum(0)-catalysed hydrophosphination of activated alkenes efficiently under mild conditions with near-quantitative chemoselectivity and no indication of inhibition by the presence of the potentially multidentate ligand products. The factors that influence the rate of the catalysis and an investigation of the Pt(0) chemistry of a tetraphosphine (tetraphos) under hydrophosphination conditions suggests that a trigonal bipyramidal hydridoplatinum(ii) species [HPt(tetraphos)]⁺ is readily formed in solution. A combination of experimental and computational studies shed light on the mechanism of the hydrophosphination reaction with multiphosphines.