Reaction of Tp(PPh3)Ru(η2-O2CCHPh2) with carbene and vinylidene precursors

Tp(PPh3)Ru(eta (2)-O2CCHPh2) (1) [Tp = tris(pyrazolyl)borate] has been prepared by the reaction of TpRu(Cl)(PPh3)(2) with 1.2 equiv of NaO2CCHPh2. Complex 1 reacts with diphenylcyclopropene to generate the metallacycle Tp(PPh3)Ru[kappa (2)-(C,O)-C(double bond CHCHPh2)OC(CHPh2)double bondO] (2). A trace of the carbene Tp(PPh3)(eta (1)-O2CCHPh2)Ru double bond CHCH double bondC(Ph)(2) (3) is also observed in the crude reaction mixture. Compound I reacts with phenyldiazomethane to form the benzylidene Tp(PPh3)(eta (1)-O2CCHPh2)Ru double bond CHPh (4). A similar species is also available by the reaction between AgO2CCHPh2 and Tp(PCy3)(Cl)Ru double bond CHCH double bondC(CH3)(2) (5), which affords Tp(PCy3)(eta (1)-O2CCHPh2)Ru double bond CHCH double bondC(CH3)(2) (6). With the addition of an excess of HCl, complexes 4 and 6 release free HO2CCHPh2 and are converted to Tp(PPh3)(Cl)Ru double bond CHPh (7) and complex 5, respectively. The reaction of I with phenylacetylene yields the five-membered chelate TP(PPh3)Ru[kappa (2)-(C,O)-C(double bond CHPh)OC(CHPh2)double bondO] (8). Complex 8 is also formed in the reaction of Tp(PPh3)(Cl)Ru double bondC double bond CHPh with 1.2 equiv of AgO2CCHPh2. Compounds 1, 2, and 8 have been characterized by X-ray crystallography. Complexes 2, 5, 6, 7, and 8 do not catalyze olefin metathesis reactions, while 4 is an active initiator for the ring-opening metathesis polymerization of norbornene.