Enamides with a free NH group have been evaluated as nucleophiles in chiral Brønsted acid-catalyzed enantioselective α-amidoalkylation reactions of bicyclic hydroxylactams for the generation of quaternary stereocenters. A quantitative structure-reactivity relationship (QSRR) method has been developed to find a useful tool to rationalize the enantioselectivity in this and related processes and t...

Using rational design, an engineered myoglobin-based catalyst capable of catalyzing the cyclopropanation of aryl-substituted olefins with catalytic proficiency (up to 46,800 turnovers) and excellent diastereo- and enantioselectivity (98-99.9%) was developed. This transformation could be carried out in the presence of up to 20 g L(-1) olefin substrate with no loss in diastereo- and/or enantiosel...

The enzymatic resolution of (R, S)-1-phenylethanol was carried out in various organic solvents. Two commercial immobilized lipases, such as ChiroCLEC-PC and Chirazyme L2, c.f., C3, lyo used in this study could exhibit the highest performance in isooctane. The effects of initial water content on the activity and enantioselectivity of the enzymes were also investigated. The method of direct conta...

(R)-1-Chloro-3-(1-naphthyloxy)-2-propanol, which is the key intermediate of (S)-propranolol, was successfully prepared via enantioselective transesterification catalyzed by lipase under ultrasound irradiation. Compared with conventional shaking, the enzyme activity and enantioselectivity were dramatically increased under ultrasound exposure. Effects of various reaction conditions on the synthet...

As an alternative to conventional asymmetric hydroformylation (AHF), asymmetric transfer hydroformylation (ATHF) by using formaldehyde as a surrogate for syngas is reported. A catalyst derived from commercially available [Rh(acac)(CO)2 ] (acac=acetylacetonate) and 1,2-bis[(2S,5S)-2,5-diphenylphospholano]ethane(1,5-cyclooctadiene) (Ph-BPE) stands out in terms of both activity and enantioselectiv...

(2R,3S)-2-Methylsulfonyloxymeihyl-3-methylsulfonyloxy-tetrahydropyran (4), derived from n-glucose, is diphenylphosphinated to (2R,3R)-2-diphenylphosphinomethyl-3-diphenylphosphino-tetrahydropyran (7), which is formed as aminor product. Compound 8 is the predominant product, formed on 3,4-elimination. Preparation and characterization of the rhodium(I) complexes 10-12 is described. Complex 10 of ...

Chiral zeolitic materials with intrinsically chiral frameworks are highly desired because they can combine both shape selectivity and enantioselectivity. In the field of zeolite, the synthesis of chiral polymorph A of zeolite Beta or chiral polymorph A-enriched zeolite Beta is one of the biggest challenges. We demonstrate here a generalized extremely concentrated fluoride route for the synthesi...

The effect of all possible mutations at position 178 on the enantioselectivity of yeast surface-bound horseradish peroxidase (HRP) toward chiral phenols has been investigated. In contrast to their wild-type predecessor, most HRP mutants are enantioselective, with the Arg178Glu variant exhibiting the greatest, 25-fold, (S)/(R) preference. Using kinetic analysis of enzymatic oxidation of various ...

Thiourea-based iminophosphorane (BIMP) organocatalysts featuring SPhos- or BIDIME phosphine units have been developed and successfully applied in the asymmetric addition of nitromethane to N-Boc-protected trifluoromethyl aryl ketimines. α-Trifluoromethyl β-nitroamines were obtained 40–82% isolated yields 80–95% enantioselectivities. A careful evaluation catalytic activity BIMPs indicates that c...