Cyclopentadienyl— und Pentamethylcyclopentadienyl—Rutheniumkomplexe mit Carboxylat-, Vinylester- und Carben-Liganden
摘要:
Monomeric carboxylatoruthenium(II) complexes [C5R5Ru(eta(2)-O2CR')(PPh3)] (R = H, Me; R' = Me, Bu-t, CF3) were prepared by ligand displacement from [(C5R5)Ru(eta(3)-2-MeC3H4)(PPh3)] and R'CO2H. From a similar route, the tosylato and pentachlorphenolato derivatives [C5H5Ru{O2SO(p-C6H4Me)}(PPh3)](n) and [C5H5Ru(eta(2)-OC6Cl5)(PPh3)] were obtained. On treatment with PhNH2, CO, PPh3 and O-2, they reacted to give the complexes [C5H5Ru{O2SO(p-C6H4Me)}(L)(PPh3)] and [C5H5Ru(OC6Cl5(CO)(PPh3)] respectively. The reaction of [C5R5Ru(eta(2)-O2CRt)(PPh3)] (R' = Me, Bu-t) with terminal alkynes HC=CR (R = CO2Me, Ph) yielded the vinylesterruthenium(II) compounds [C5H5Ru(kappa(2)(C,O)-C(=CHR)OC(R')=O}(PPh3)] for which a resonance structure involving a carboxylato(vinylidene) species is postulated. The carbene half-sandwich type complexes [C5H5RuCl(=CRR')(PPh3)] (R and R' = C6H4X) were prepared in two steps from [C5H5Ru(eta(2)-O2CMe)(PPh3)], N2CRR' and either Al2O3/Cl- or Et3NHCl. The molecular structure of [C5Me5Ru(eta(2)-(O2CBu)-Bu-t)(PPh3)] and [C5H5RuCl(=CPh2)(PPh3)] have been determined by X-ray single-crystal structural investigations.
Half-Sandwich Ruthenium(II) Catalysts for C−C Coupling Reactions between Alkenes and Diazo Compounds
作者:Walter Baratta、Wolfgang A. Herrmann、Roland M. Kratzer、Pierluigi Rigo
DOI:10.1021/om0003537
日期:2000.9.1
The complex [(eta(5)-C5H5)Ru(PPh3)(2)Cl] (1) and other readily available ruthenium(II) derivatives of general formula [(eta(5)-ligand)Ru(PR3)(2)X] efficiently catalyze the cyclopropanation of styrene and other electron-rich alkenes in the presence of ethyl diazoacetate with a high cia stereoselectivity. When diphenyldiazomethane is employed as carbene source, the reaction with styrene, catalyzed by 1, affords mainly 1,1,3-triphenylpropene, as result of a formal :CPh2-:CHCH2Ph coupling. Furthermore, appreciable amounts of the metathesis and cyclopropanation products I,1-diphenylethene and 1,2-diphenylcyclopropanes in a I:1 molar ratio are observed. The carbene complex [(eta(5)-C5H5)Ru(=CPh2)(PPh3)Cl] (13), which was detected during the catalytic process, can be readily obtained in 85% isolated yield from 1 and diphenyldiazomethane in a one-pot reaction. With styrene, complex 13 undergoes a stoichiometric carbene transfer reaction, yielding the same organic products observed in the catalytic process with 1.