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The asymmetric addition reactions between varied nonaromatic aldehydes and diethylzinc catalyzed by chiral phosphoramide L 1 and thiophosphorodiamide L 4 were thoroughly investigated. Both ligands worked very well for α-branched aliphatic and α-branched α,β-unsaturated aldehydes. For α-nonbranched aliphatic aldehydes, L 4 behaved much better than L 1 . For α-nonbranched α,β-unsaturated aldehydes, L 4 showed high enantioselectivities and L 1 only gave racemic alcohol products. [ABSTRACT FROM AUTHOR]

[Display omitted] In this study, an alcohol dehydrogenase derived from Lactobacillus kefir (LkADH) was engineered and a simple and practical bioreduction system was developed for the preparation of (R)-2-chloro-1-(2, 4-dichlorophenyl) ethanol ((R)-CDPO), a key intermediate for the synthesis of antifungal drugs. Through active pocket iterative saturation mutagenesis, mutant LkADH-D18 (Y190C/V196L/M206H/D150H) was obtained with high stereoselectivity (99% ee, R vs 87% ee , S) and increased activity (0.44 µmol·min−1·mg−1). LkADH-D18 demonstrated NAD(P)H regeneration capability using a high concentration of isopropanol (IPA) as a co-substrate. Using 40% IPA (v/v), 400 mM of (R)-CDPO (90.1 g·L-1) was obtained via complete substrate conversion using 40 mg·mL−1 LkADH-D18 wet cells. The biocatalytic process catalyzed at constant pH with the cheap co-solvent IPA contributed to improved isolated yield of (R)-CDPO (97%), lower reaction cost, and simpler downstream purification, indicating the potential utility of LkADH-D18 in future industrial applications. [ABSTRACT FROM AUTHOR]