77 research outputs found
Practical synthesis of enantiopure benzylamines by catalytic hydrogenation or transfer hydrogenation reactions in isopropanol using a Ru-pybox catalyst
No full textThe screening of a family of complexes of the formula [RuCl(R-pybox)(L)] (R-pybox = Ph-, Pr- or indane-pybox; L = monodentate P, N or C ligand) in the enantioselective hydrogenation of N-aryl imines indicates a strong influence of the R-pybox substituents and the L ligand in the process. A comparison indicates that the best results are obtained with the complex [RuCl(Ph-pybox)(PPh(OMe))] which provided values of 99% ee for the reduction of several imines derived from aryl alkyl ketones. It is worth noting that this complex is capable of reducing the mentioned imines under transfer hydrogenation conditions using isopropanol as a hydrogen donor with equally high enantioselectivities.We gratefully thank the Ministerio de Economia, Industria y Competitividad of Spain for financial support (Grants CTQ2013-42501-P, CTQ2016-75193-P and CTQ2016-81797-REDC; AEI/FEDER, UE). E. de J. and E. M. P. thank the FICYT (Principado de Asturias, Spain) for a Ph.D. fellowship.
MINECO/ICTI2013-2016/CTQ2016-75193-P
MINECO/ICTI2013-2016/CTQ2016-81797-RED
1,3-Dipolar Cycloadditions of Ruthenium(II) Azido Complexes with Alkynes and Nitriles
No full textThe diazido complex [Na]Â[RuÂ(N<sub>3</sub>)<sub>2</sub>{Îș<sup>3</sup>(<i>N</i>,<i>N</i>,<i>N</i>)-Tpms}Â(PPh<sub>3</sub>)] (<b>1</b>) (Tpms = trisÂ(pyrazolyl)Âmethanesulfonate) has been synthesized,
and its reactivity toward dipolarophiles has been investigated. Thus,
the reaction of <b>1</b> with alkynes leads to complexes with
one or two triazolate ligands depending on the alkyne and the reaction
conditions. Complex <b>1</b> also reacts with nitriles. Thus,
the reaction with RCN (R = Me, Ph) leads to the substitution products
[RuÂ(N<sub>3</sub>)Â(NCR)Â{Îș<sup>3</sup>(<i>N</i>,<i>N</i>,<i>N</i>)-Tpms}Â(PPh<sub>3</sub>)]. However,
when fumaronitrile is used, a complex containing a new Îș<sup>2</sup>(<i>N</i><sup>1</sup>,<i>N</i><sup>3</sup>)-5-(1,2,3-triazol-4-yl)-1,2,3,4-tetrazolate ligand is obtained as
the result of two consecutive cycloaddition reactions. The mechanism
for this unusual reaction has been unambiguously established through
the isolation of the intermediate complex resulting from a first cycloaddition
between a coordinated azide and the Cî»C double bond
Activation of 2-Propyn-1-ol Derivatives by Indenylruthenium(II) and -osmium(II) Complexes: X-ray Crystal Structures of the Allenylidene Complexes [M(CCCPh 2
No full textSynthesis, Structural Characterisation and Electrochemical Studies of Neutral Alkenylcarbyne Tungsten Complexes Bearing Chelating Bidentate and Tridentate Phosphanes
No full textRegio- and Diastereoselective Nucleophilic Additions of Lithium Enolates on the Allenylidene Complexes [Ru{CCC(R)Ph}(η 5
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Metallacumulenylidene complexes in the Cycloheptatrienyl Molybdenum series [Mo{(C)n=CR2}L2(?-C7H7)]+ (n = 0, 1, 2; L2 = P-donor ligand). X-ray crystal structures of [Mo{C=C(H)Ph}{P(OMe)3}2(?-C7H7)][BF4] and [Mo(C=C=CPh2)(dppe)(?-C7H7)][PF6] and DFT investigation of cumulenylidene ligand orientations.
No full textNovel Copper(I) Complexes Containing 1,1â-Bis(diphenylphosphino)ferrocene (dppf) as a Chelate and Bridging Ligand: Synthesis of Tetrabridged Dicopper(I) Complexes [Cu 2
No full textSynthesis and Second-Order Nonlinear Optical Properties of DonorâAcceptor Ï-Alkynyl and Ï-Enynyl Indenylruthenium(II) Complexes. X-ray Crystal Structures of [Ru{CâźCCHC(C 6
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