Biotransformation of ten α-haloacetophenones in the growing culture of the strain Rhodotorula rubra KCh 82 has been carried out. Nine of the substrates underwent an effective enantioselective reduction to the respective (R)-alcohols according to Prelog's rule, with the exception of 2-chloro-1,2-diphenylethan-1-one that was not transformed by this strain. The expected reduction proceeded without...

Methods for the direct chiral chromatographic separation of the four stereoisomers of meta-hydroxyphenylpropanolamine (MHPA) on an analytical and preparative scale are described. Separations were carried out on a Crownpak CR (+) chiral column with 113 mM aqueous perchloric acid as the mobile phase. Baseline resolution of the more retained (+)-stereoisomers (1S configuration) and partial resolut...

Enantioenriched alcohols are ubiquitous in the structures and syntheses of natural products and pharmaceuticals. Catalytic, asymmetric alcohol oxidation can be a useful method to access these molecules.[1] Previously, we reported the development of an aerobic kinetic resolution of alcohols by catalytic [Pd(nbd)Cl2] (1, nbd = norbornadiene) and the naturally occurring alkaloid (−)-sparteine (sp,...

Phenylacetaldehyde reductase (PAR) produced by styrene-assimilating Corynebacterium strain ST-10 was used to synthesize chiral alcohols. This enzyme with a broad substrate range reduced various prochiral aromatic ketones and beta-ketoesters to yield optically active secondary alcohols with an enantiomeric purity of more than 98% enantiomeric excess (e.e.). The Escherichia coli recombinant cells...

A series of chiral enantiomerically pure aziridines containing a phosphine moiety were synthesized and successfully applied as organocatalysts in asymmetric intramolecular Rauhut–Currier reactions p-quinone derivatives. The desired phenols achieved high chemical yields with satisfactory values enantiomeric excess (up to 98% ee, some cases). stereochemical course the title reaction may be contro...

A one-pot chemoenzymatic sequential cascade for the synthesis of chiral amines from alkynes was developed. In this integrated approach, just ppm amounts gold catalysts enabled conversion to ketones (>99%) after which a transaminase used catalyze production biologically valuable in good yield (up 99%) and enantiomeric excess (>99%). preparative scale (S)-methylbenzylamine (S)-4-methoxy-methylben...

Complexes of cyclodextrins with amino acid analytes are produced in the gas phase and are ideal for the study of molecular recognition. In this Account, we discuss the evidence for the presence of gas-phase inclusion complexes and the nature of the interaction. The use of cyclodextrins as chiral selectors in gas-phase guest-exchange reactions is illustrated, and the nature of the enantioselecti...

A catalytic asymmetric conjugate arylation of acyclic alpha,beta-unsaturated ketones with arylboronic acids was catalyzed by 3 mol% of chiral amidomonophosphane 1-rhodium(I) in the presence of potassium hydroxide in a mixture of 1,4-dioxane and water at 70 degrees C to afford 1,4-conjugate arylated acyclic ketones with high enantiomeric excess in high chemical yield. Thirteen examples of the re...

Enantiodifferentiating photoisomerization of (Z)-cyclooctene sensitized by (R)- or (S)-1-methylheptyl benzoate immobilized in zeolite supercages afforded the respective enantiomer pair, (-)- and (+)-(E)-isomer (1E) in 5% enantiomeric excess, whilst racemic 1E was obtained upon homogeneous-phase photosensitization with the same antipodal sensitizer pair, thus demonstrating for the first time tha...