New Rhodacarborane−Phosphoramidite Catalyst System for Enantioselective Hydrogenation of Functionalized Olefins and Molecular Structure of the Chiral Catalyst Precursor [3,3-{(S)-PipPhos}2-3-H-1,2-(o-xylylene)-closo-3,1,2-RhC2B9H9]

2011 ◽  
Vol 30 (7) ◽  
pp. 1942-1950 ◽  
Author(s):  
Leonid S. Alekseev ◽  
Sergey E. Lyubimov ◽  
Fedor M. Dolgushin ◽  
Valentin V. Novikov ◽  
Vadim A. Davankov ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Enantioselective Hydrogenation ◽  
Catalyst System ◽  
Catalyst Precursor ◽  
Chiral Catalyst

Application of [Ru((R)-BINAP)(MeCN)(1-3:5,6-η-C8H11)](BF4) as a catalyst precursor for enantioselective hydrogenations

1998 ◽  
Vol 76 (10) ◽  
pp. 1447-1456 ◽  
Author(s):  
Christopher JA Daley ◽  
Jason A Wiles ◽  
Steven H Bergens
Keyword(s):  
Carboxylic Acid ◽  
Type Systems ◽  
Enantioselective Hydrogenation ◽  
Catalyst System ◽  
Structural Features ◽  
Catalyst Precursor ◽  
Unsaturated Carboxylic Acid ◽  
Tiglic Acid ◽  
Protic Solvents ◽  
Acid Methyl

A catalyst system employing [Ru((R)-BINAP)(MeCN)(1-3:5,6-η-C8H11)](BF4) as catalyst precursor was evaluated using the enantioselective hydrogenations of tiglic acid, α-acetamidocinnamic acid, itaconic acid, methyl tiglate, dimethyl itaconate, geraniol, ethyl acetoacetate, and dimethyl oxaloacetate as a series of typical substrates. Acetone and MeOH were used as model aprotic and protic solvents, respectively. The hydrogenation of substrates containing an α, β-unsaturated carboxylic acid functionality required stoichiometric quantities of NEt3 to occur at reasonable rates in acetone solution, while in MeOH solution it did not. The enantioselectivities were typically higher in acetone than in MeOH. This catalyst system is among the more enantioselective ruthenium-BINAP type systems reported for the catalytic hydrogenation of substrates containing an α, β-unsaturated acid or ester functionality. The enantioselectivities for the hydrogenation of ketones ranged from poor (15%) to moderate (74%). 1,4-Dicarboxylate substrates with the prochiral olefin or ketone at the 2-position were all hydrogenated in good to high ee with the same enantioface selectivity both with our system and other catalysts reported in the literature. This raised the possibility that these substrates were hydrogenated through intermediates with similar structural features. Key words: ruthenium, BINAP, enantioselective, hydrogenation, catalysis.

Synthesis and X -Ray Crystal Structure of the Heterobimetallic Complex [FeRh (μ-CO)(CO)3((μ-PBut2)((μ-Ph2PCH2PPh2)]

1997 ◽  
Vol 52 (7) ◽  
pp. 810-814 ◽  
Author(s):  
Hans-Christian Böttcher ◽  
Kurt Merzweiler ◽  
Clemens Bruhn
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Room Temperature ◽  
Metal Carbonyl ◽  
Homogeneous Catalyst ◽  
Catalyst Precursor ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Heterobimetallic Complex

Abstract The reaction of the phosphido-bridged metal carbonyl [FeRh(CO)6(μ-PBut2)] (1) with dppm [dppm = bis(diphenylphosphino)methane] leads to the heterobimetallic complex [FeRh(μ-CO)(CO)3(μ-PBut2)(μ-dppm)] (2) in good yields. The molecular structure of 2 was determined at room temperature [triclinic, space group P1̄, a = 9.509(6), b = 13.637(5), c = 14.926(8) Å, α = 81.38(4), β = 82.75(4), γ = 71.25(4)°]. The compound acts as a homogeneous catalyst precursor in the hydroformylation reaction of ethylene, but it decomposes during this process.

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