Hybrid quantum mechanics/molecular mechanics (QM/MM) methods were employed to study electronic effects of 5,5'-substituents on the enantioselectivity of (salen)Mn catalysts. Correlations obtained from the QM/MM calculations elucidated electronic framework effects on enantioselectivity for (salen)Mn heterogenized in a metal-organic framework (MOF). The correlations also enabled fast ligand scree...

Here we found that the enantioselectivity of G-quadruplex DNA-based Diels-Alder reaction can be switched by just changing Na(+) to K(+), which is ascribed to the structural transformation of the G-quadruplex from antiparallel to hybrid-type. By tuning the ratio of Na(+)/K(+), the enantioselectivity of the Diels-Alder reaction could be switchable and shows much more sensitive to K(+) than to Na(+).

Four new chiral polymers of BINOLSalen-cobalt ACHTUNGTRENNUNG(III) salt complexes have been designed, synthesized and applied to the direct fabrication of chiral propylene carbonate from racemic propylene oxide. The (R/S)-polymer catalyst 2 and (S/R)-polymer catalyst 4 exhibit better enantioselectivity than the (R/R)-polymer catalyst 1 and the (S/S)-polymer catalyst 3 and have been recovered an...

The combination of the ionic liquid co-lyophilized lipase and microwave irradiation was used to improve enzyme performance in enantioselective esterification of α-lipoic acid. Effects of various reaction conditions on enzyme activity and enantioselectivity were investigated. Under optimal condition, the highest enantioselectivity (E = 41.2) was observed with a high enzyme activity (178.1 μmol/h...

A newly isolated Galactomyces geotrichum ZJUTZQ200 strain containing an epoxide hydrolase was used to resolve racemic ethyl 3-phenylglycidate (rac-EPG) for producing (2R,3S)-ethyl-3-phenylglycidate ((2R,3S)-EPG). G. geotrichum ZJUTZQ200 was verified to be able to afford high enantioselectivity in whole cell catalyzed synthesis of this chiral phenylglycidate synthon. After the optimization of th...

Enzyme selectivity towards a particular enantiomeric configuration of substrate is necessarily governed by chemical and spatial relationships between the substrate and the enzyme binding cavity. In the case of Candida antarctica lipase B experimental evidence shows that enantioselectivity of the enzyme towards the alcohol moiety 3-methyl-2-butanol varies significantly with respect to the chain ...

The immobilization of the chiral complex RhDuphos, by electrostatic or π-π (adsorption) interactions, on carbon nanotubes and carbon xerogels is investigated. To promote such interactions, the supports were either oxidized or heat treated to create carboxylic type surface groups or an apolar surface, respectively. The catalysts were tested in the hydrogenation of methyl 2-acetamidoacrylate. The...

The regio- and enantioselectivity of the reduction of an NAD model compound having axial chirality with respect to the C(3)(quinolinium)-C(carbonyl) bond, 3-piperidinylcarbonyl-1,2,4-trimethylquinolinium ion (1), by using several reducing agents is described. Reaction of 1 with sodium hydrosulfite affords the 1,4-reduced product, 3-piperidinylcarbonyl-1,2,4-trimethyl-1,4-dihydroquinoline (), wi...

The substitution of the oxyanion Q114 with Met and Leu was carried out to investigate the role of Q114 in imparting enantioselectivity on T1 lipase. The mutation improved enantioselectivity in Q114M over the wild-type, while enantioselectivity in Q114L was reduced. The enantioselectivity of the thermophilic lipases, T1, Q114L and Q114M correlated better with log p as compared to the dielectric ...