Insertion of ethyl diazoacetate into the platinum-carbon bond of Pt(diphosphine)(halide)(aryl) complexes. X-ray structure of the Pt{(2S,4S)-bdpp)}I(Ph) complex

Pt(diphosphine)X(aryl) complexes [diphosphine = 1,3-bis(diphenylphosphino) propane (dppp), 2,4-bis(diphenylphos phino)pentane (bdpp); aryl = phenyl, 2-thiophenyl; X = Cl, I] have been reacted with ethyl diazoacetate in chloroform. It has been revealed by in situ n.m.r. studies that the starting compounds insert the carbene, formed from ethyl diazoacetate, into the Pt-aryl group resulting in Pt(diphosphine)X{CH(aryl)COOC2H5}. Depending on the reaction conditions (reaction time, ratio of the reactants) and the ligands various side-reactions have been observed: (i) the formation of Pt(diphosphine)X2 in chloroform, (ii) the insertion of the :CHCOOC2H5 fragment into the Pt-halide bond of the dihalogeno complexes Pt(diphosphine)X2 resulting in the exclusive formation of Pt(diphosphine)X(CHXCOOC2H5). Diastereoselective insertion reactions have been observed in the presence of (S,S)-bdpp as diphosphine. The Pt{(S,S)-bdpp)}I(Ph) complex has been characterized by X-ray crystallography.