19128-84-8Relevant academic research and scientific papers
Asymmetric hydrogenation of α,β-unsaturated carboxylic acids catalyzed by ruthenium(II) complexes of spirobifluorene diphosphine (SFDP) ligands
Cheng, Xu,Xie, Jian-Hua,Li, Sheng,Zhou, Qi-Lin
, p. 1271 - 1276 (2007/10/03)
The ruthenium diacetate complexes ligated by chiral spirobifluorene diphosphines (SFDP) were very effective catalysts for the asymmetric hydrogenation of tiglic acid derivatives and α-methylcinnamic acid derivatives with high activities and excellent enantioselectivities (up to 98% ee). The α-aryloxybutenoic acids can also be hydrogenated by these catalysts to provide the corresponding saturated α-aryloxybutanoic acids in high yields (89-93%) and enantioselectivities (up to 95% ee). In this reaction, the SFDP ligand with para-methyl groups on the P-phenyl rings gave the best results.
Enantioselective hydrogenation of α-aryloxy α,β- unsaturated acids. Asymmetric synthesis of α-aryloxycarboxylic acids
Maligres, Peter E.,Krska, Shane W.,Humphrey, Guy R.
, p. 3147 - 3150 (2007/10/03)
(Chemical Equation Presented) A facile preparation of chiral α-aryloxy carboxylic acids via asymmetric hydrogenation of the corresponding unsaturated acids has been discovered. A number of catalysts have been identified that give high product enantioselectivity, and the scope of the reaction has been examined with respect to substitution on the aromatic ring and olefin.
Enzymatic enantioselective ester hydrolysis by carboxylesterase NP
Smeets, J. W. H.,Kieboom, A. P. G.
, p. 490 - 495 (2007/10/02)
The enzymatic hydrolysis of a series of carboxylic esters by carboxylesterase NP has been investigated in order to determine the scope and limitations of this enzyme. 2-Substituted propionates were hydrolyzed with high enantioselectivity when an aromatic moiety was part of the 2-substituent.Enantioselective hydrolysis could be accomplished with several 2-arypropionates, 2-(aryloxy)propionates and N-arylalanine esters.The propionate esters yielded propionic acids as (S) enantiomers, whereas the alanine esters yielded the (R) enantiomers.Without a 2-aryl substituent, the enzymatic hydrolysis of the propionates occurred at a lower rate without acceptable enantioselectivity.In addition to 2-substituted propionates, only a few other esters were hydrolyzed with high enantioselectivity by carboxylesterase NP, such as some prochiral disubstituted malonates. 1-Phenylethylacetate was the only substrate with chirality in the alcohol part of the ester that was found to be hydrolyzed enantioselectively.Carboxylesterase NP proved to be a powerful enzyme for kinetic resolution of propionate esters with an aromatic ring containing a 2-substituent.
