III International Conference

PP-I-4reaction conditions, 100% conversion of white phosphorus to organophosphorus products isachieved with high selectivity in P(III) esters (ca. 95%). The catalytic oxidation of P 4 byorganic peroxides in alcohols is proposed to proceed with the same stepwise radicalmechanism, the only difference being in the preliminary step of peroxide homolysis which isnow replaced by the metal assisted reduction of the peroxide to yield the radical R’O ● and theanion R”O - (Scheme 1).P 4ROHCuX 2 R'O + R"O -CuX 21-3(ca. 1%)CuCuXR'OOR"Scheme 1It should be emphasized that the active catalytic species which accelerate thedecomposition of peroxides are not the initial Cu(II) but the Cu(I) ions, which are formed insitu via the fast reduction of Cu(II) to Cu(0) by white phosphorus followed bycomproportionation of Cu(0) and Cu(II). The reduction of Cu(II) by P 4 in alcohol agrees witha heterolytic reaction pathway [2]:P 4 + 6CuX 2 + 12ROH 4P(O)H(OR) 2 + 6Cu + 4RX + 8HX (4)1However, taking into account the stoichiometry of the reaction (4) and thesubstoichiometric amount of CuX 2 used (5-10 mol % with respect to P 4 ), one can envisagethat the contribution of this alternative reaction to the synthesis of organophosphoruscompounds should be very low (ca. 1%). Our experimental results therefore show that thecopper salts catalyzed oxidation of white phosphorus by organic peroxides in alcohols isalmost completely accomplished via the radical pathway (eqs. 1-3) where the production ofRO ● radicals is boosted by the Cu(I) ions as highlighted in Scheme 1.This study is supported by the research grants from BASF, INTAS 00-00018 andISTC K-754p.References1. (a) R.A. Sheldon, J.A. Van Doorn, J. Cat. 31 (1973) 427; (b) R.I. Volnyanskaya etc, Ukrain.Khim. Zhurn. 70 (2004) 99; (c) M.B. Andrus, Z. Zhou, J. Am. Chem. Soc. 124 (2002) 8806;(h) Z. Li, C.-J. Li, H. J. Am. Chem. Soc. 127 (2005) 3672.2. (a) Ya.A. Dorfman, R.R. Abdreimova, Zh. Obshch. Khim. 63 (1993) 289; (b) Ya.A. Dorfman,R.R. Abdreimova, D.N. Akbayeva, Kinet. Katal. 36 (1995) 103.14