Hexachlorocyclohexane dehydrochlorinase (LinA) mediates dehydrochlorination of γ-HCH to 1, 3, 4, 6-tetrachloro-1,4-cyclohexadiene that constitutes first step of the aerobic degradation pathway. We report the 3.5 Å crystal structure of a thermostable LinA-type2 protein, obtained from a soil metagenome, in the hexagonal space group P6(3)22 with unit cell parameters a = b = 162.5, c = 186.3 Å, res...

Density functional theory calculations have been used to investigate the hydrogenation of acetophenone (ACP) catalysed by the RuH(2)(diphosphine)(diamine) complexes with emphasis on the effect of the structure of the diphosphine and diamine ligands on the enantioselectivity. The computed reaction coordinate diagrams of RuH(2)(diphosphine)[(S,S)-DPEN] catalysed reactions with different (S)-dipho...

The reaction of chiral sulfur ylides with aldehydes and ketones has emerged as a useful asymmetric process for the synthesis of epoxides. Processes employing either catalytic or stoichiometric amounts of sulfides have been developed. Although a large number of chiral sulfur ylides have been tested in the epoxidation process, only a few have delivered high diastereo- and enantio- selectivity. Th...

Different strategies for the resolution of racemates in lipase catalyzed hydrolyses, esterifications, and transesterifications are presented. The importance of the equilibrium conversion for the optimization of the enantiomeric excess is emphasized. Investigations have been carried out on esters of 1-phenylethanol and 2methylalkanoic acids. Results are presented, which provide general informati...

The discrimination between different enantiomers of chiral compounds by the biological system is medically important as the pharmacological and toxicological effects of enantiomeric drugs significantly differ depending on their stereostructures. One enantiomer is preferred over its enantiomeric counterpart and a racemic mixture for higher activity or lower toxicity. Such enantioselectivity has ...

Carbonic anhydrase is a zinc metalloenzyme that catalyzes the hydration of carbon dioxide to bicarbonate. Replacing the active-site zinc with manganese yielded manganese-substituted carbonic anhydrase (CA[Mn]), which shows peroxidase activity with a bicarbonate-dependent mechanism. In the presence of bicarbonate and hydrogen peroxide, (CA[Mn]) catalyzed the efficient oxidation of o-dianisidine ...

The yield and enantioselectivity of an asymmetric aldol reaction, catalyzed by a proline derivative immobilized on polystyrene via dipolar cycloaddition, are remarkably improved by the dendronization of the support.

Asymmetric addition of arylboroxines to β-alkoxyacrylate esters proceeded in the presence of a rhodium complex coordinated with a chiral diene ligand to give high yields of β-alkoxy-β-arylcarboxylic acid esters with very high enantioselectivity.

L-Pipecolinic acid derived Lewis basic N-formamide has been developed as a first highly effective catalyst for the asymmetric reduction of aromatic and aliphatic ketones as well as aromatic and aliphatic ketimines in good to high enantioselectivity.

Palladium-catalyzed asymmetric 1,6-addition of diarylphosphines to electron-deficient dienes was developed through rational selection of electron-withdrawing groups on the dienes. Various chiral allylic phosphine derivatives were synthesized in good yields with high enantioselectivity (up to 96% ee).