Intramolecular carbon-carbon coupling reactions of a kappa(2)(P,P)-bis(diphenylphosphino)methanide ligand with unsaturated carbene moieties in indenyl-ruthenium(II) complexes

Treatment of disubstituted indenyl-ruthenium(II) vinylidene complexes [Ru{= C=C(Me)R}(eta (5)-C9H7)(dppm)][CF3SO3] (R = Bu-t (4a), Ph (4b); dppm = bis( diphenylphosphino)methane) with NaOMe results in the deprotonation of the c oordinated dppm ligand to give a kappa (2)(P,P)-(Ph2P)(2)CH ligand. Subsequ ent intramolecular nucleophilic attack of the methanide group on the electr ophilic vinylidene a-carbon gives the alkenyl metallacycles (Z)-[Ru{kappa ( 3)(C,P,P)-C=C(Me)R(Ph2CHPPh2)}(eta (5)-C9H7)] (R = tBu (6a), Ph (6b)). The related metallacycle species [Ru{kappa (3)(C,P,P)-C(OMe)=C(OMe)=C(H)C(H)R(P h2PCHPPH2)}(eta (5)-C9H7)] (R = H (11a), Ph (11b)) have also been prepared. They have been obtained through an analogous carbon-carbon coupling proces s involving the bisdiphenylphosphino)methanide anion, generated by the trea tment of the alpha,beta -unsaturated methoxy-carbene derivatives [Ru{=C(OMe )C(H)=C(H)R}(eta (5)-C9H7)(dppm)][PF6] (R = H (9a), Ph (9b)) and (LiBu)-Bu- t, and the C-gamma atom of the unsaturated carbene ligand. (C) 2001 Elsevie r Science B.V. All rights reserved.