Functionalized ylides: new trends in organometallic chemistry

The coordination and organometallic chemistry of P-and As-carbonyl stabilized ylides is reviewed. As a general feature, the coordination chemistry of R3ECHCOR'-type (E = P, As) ligands appears to be dominated by C(ylide) metal coordination, although a few examples of O(ylide)-bound complexes are known. The factors addressing C(ylide)-vs. O(ylide)-coordination in Pt(II) and Pd(II) systems are examined. The Ni(II) complexes containing P,O-chelate ylide ligands are also discussed, with a special emphasis on their catalytic activity. The synthesis and reactivity of phosphonium functionalized isocyanides and their corresponding ylides, which provide a new route to metal coordinated indole systems, are described. Finally, the reactivity of Ph3PC=C=O towards metal substrates is summarized including the formation of ketenyl complexes. (C) 1998 Elsevier Science S.A.