The mechanism of asymmetric hydrogenation. Chiral bis(diphenylphosphino)-α-phenylalkane complexes in catalytic and structural studies

A New Route to Cationic Half‐Sandwich Ruthenium(II) Complexes with Chiral Cyclopentadienylphosphane Ligands

“…(R)-1-Phenylethane-1,2-diol was obtained by reduction of (R)-mandelic acid with LAH. [31] (S)-1-Cyclohexylethane-1,2-diol was obtained by initial reduction of the arene ring of (S)-mandelic acid with hydrogen using 5% Rh on alumina as catalyst, followed by reduction of the carboxylic group with LAH. [32] (R)-3-Phenylpropane-1,2-diol was obtained by reduction of the corresponding acid with LAH.…”

“…At first, 2 may be formed, with subsequent coordination of phosphorus to afford 3. The reaction has been followed by means of a 31 P NMR experiment, revealing the formation of intermediate species with 31 P resonances at about δ ϭ 30 ppm. The coordination of the phosphorus atom seems to be very fast, as no signals of the free ligands could be observed (δ ϭ 0.4 and 0.9 ppm).…”

Facile Reduction of Aromatic Aldehydes, Ketones, Diketones and Oxo Aldehydes to Alcohols by an Aqueous TiCl3/NH3 System: Selectivity and Scope

“…Phenyl-1,4-pentanediol (5f) and 5-Hydroxy-5-phenylpentan-2-one (6f): After workup, the residue, purified by flash column chromatography (hexane/EtOAc, 7:3), afforded 6f as a yellow oil (0.62 g, 70%) and traces (30 mg, 3.2%) of 5f as a 1:1 mixture of the two isomers. [29] this diol ought to be the syn (ϵ dl) isomer; according to ref. [31] , however, the 13 C NMR spectrum of 5g revealed the presence of both isomers (1:1).…”

Enzymatic resolution of 1-phenyl-1,2-ethanediol by enantioselective oxidation: Overcoming product inhibition by continuous extraction

“…This article deals with the kinetic resolution of 1-pheny1-1,2-ethanediol carried out by an alcohol dehydrogenase. (S)-l-Phenyl-1,2-ethanediol is used as a precursor for the production of chiral biphosphines, which are used as ligands in cationic rhodium complexes for the asymmetric hydrogenation of prochiral alkenes (Brown and Murrer, 1982). This diol has also been used as a chiral initiator for stereoselective polymerization (Leborgne et al, 1979).…”