Isomerization and Deuterium Scrambling Evidence for a Change in the Rate-Limiting Step during Imine Hydrogenation by Shvo's Hydroxycyclopentadienyl Ruthenium Hydride
作者:Charles P. Casey、Jeffrey B. Johnson
DOI:10.1021/ja044450t
日期:2005.2.1
mechanism analogous to that proposed for aldehyde and ketone reduction. Reduction of electron-rich N-alkyl-substituted imine, N-isopropyl-(4-methyl)benzilidene amine (9), was accompanied by facile imine isomerization and scrambling of deuterium labels from reduction with 5-RuDOH into the N-alkyl substituent of both the amine complex and into the recovered imine. Inverse equilibrium isotope effects were
Reduction of Imines by Hydroxycyclopentadienyl Ruthenium Hydride: Intramolecular Trapping Evidence for Hydride and Proton Transfer Outside the Coordination Sphere of the Metal
作者:Charles P. Casey、Galina A. Bikzhanova、Qiang Cui、Ilia A. Guzei
DOI:10.1021/ja053956o
日期:2005.10.1
Reduction of imines by [2,5-Ph-2-3,4-Tol(2)(eta(5)-C4COH)]Ru(CO)H-2 (2) produces kinetically stable ruthenium amine complexes. Reduction of an imine by 2 in the presence of an external amine trap gives only the complex of the newly generated amine. Reaction of 2 with H2N-p-C6H4N=CHPh (11), which contains an intramolecular amine trap, gave a 1:1 mixture of [2,5-Ph-2-3,4-Tol(2)(eta(4)-C4CO)](CO)(2)RuNH(CH2Ph)(C6H4-p-NH2) (8), formed by coordination of the newly generated amine to the ruthenium center, and [2,5-Ph-2-3,4-Tol(2)(eta(4)-C4CO)](CO)(2)RuNH2C6H4-p-NHCH2Ph (9), formed by coordination of the amine already present in the substrate. These results require transfer of hydrogen to the imine outside the coordination sphere of the metal to give a coordinatively unsaturated intermediate that can be trapped inside the initial solvent cage. Amine diffusion from the solvent cage must be much slower than coordination to the metal center. Mechanisms requiring prior coordination of the substrate to ruthenium would have led only to 8 and can be eliminated.
Shukla; Fadayan; Khan, Journal of the Indian Chemical Society, 1988, vol. 65, # 3, p. 225 - 226
作者:Shukla、Fadayan、Khan、Bhar
DOI:——
日期:——
Catalytic Acceptorless Dehydrogenation of Amines with Ru(P<sup>R</sup><sub>2</sub>N<sup>R′</sup><sub>2</sub>) and Ru(dppp) Complexes
作者:James M. Stubbs、Richard J. Hazlehurst、Paul D. Boyle、Johanna M. Blacquiere
DOI:10.1021/acs.organomet.6b00870
日期:2017.5.8
[Ru(Cp)((P2N2Bn)-N-Ph)(MeCN)]PF6 (1; (P2N2Bn)-N-Ph = 1,5-benzyl-3,7-phenyl-1,5-diaza-3,7-diphosphacyclooctane) and [Ru(Cp)(dppp)(MeCN)]PF6 (2; dppp = 1,3-bis(diphenylphosphino)propane) are both active toward the acceptorless dehydrogenation of benzylamine (BnNH2) and N-heterocycles. The two catalysts have similar activities but different selectivities for dehydrogenation products. Independent synthesis of a [Ru(Cp)((P2N2Bn)-N-Ph)(NH2Bn)]PF6 adduct (3) reveals the presence of a hydrogen bond between the bound amine and the pendent base of the (P2N2Bn)-N-Ph ligand. Preliminary mechanistic studies reveal that the benzylamine adduct is not an on-cycle catalyst intermediate.