title: Effect of solvent polarity on enantioselectivity in Candida antarctica lipase B catalyzed kinetic resolution of primary and secondary alcohols.
abstract: The Candida antarctica lipase B (CAL-B) catalyzed kinetic resolution of primary and secondary alcohols via acetylation is dependent on the permittivity (ε) of the reaction solvent. For example, the enantiomeric ratio (E) vs ε plot for the acetylation of 1-(naphth-2-yl)ethanol (1) exhibits a convex shape, taking the maximum E value at a medium ε value (11.2), whereas the same plot for the acetylation of benzyl 3-hydroxybutylate (3) exhibits a concave shape, taking the minimum E value at a similar ε value (11.6). Kinetic studies reveal that the difference in shape of the E vs ε plots originates from the relative reaction rate between the enantiomers with different Michaelis constants (Km). Thus, when the enantiomer with a larger Km value in the middle ε region reacts more slowly than its antipode, the ε dependence of E exhibits a convex shape. On the other hand, when the enantiomer reacts more quickly, it exhibits a concave shape. The E vs ε plot for the acetylation of 2-methoxy-2-phenylethanol (7) exhibits a convex shape with the maximum E value (20) at ε = 14.1. The E value can be further improved to almost reach the efficiency required for industrial applications (E ≈ 30) by the addition of a nitro compound.
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, 6-6-11 Aramaki-Aoba, Aoba-ku, Sendai 980-8579, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kitamoto
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, 6-6-11 Aramaki-Aoba, Aoba-ku, Sendai 980-8579, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kuruma
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, 6-6-11 Aramaki-Aoba, Aoba-ku, Sendai 980-8579, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, 6-6-11 Aramaki-Aoba, Aoba-ku, Sendai 980-8579, Japan.
authors.forename: Tetsutaro
authors.initials: T
authors.lastname: Hattori
mesh_terms: D000438:Alcohols / Q000737:chemistry* / Q000378:metabolism*; D055162:Biocatalysis / Q000187:drug effects; D004952:Esters / Q000737:chemistry / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D012997:Solvents / Q000737:chemistry* / Q000494:pharmacology*; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D004952:Esters; D005656:Fungal Proteins; D012997:Solvents; D008049:Lipase; C431349:lipase B, Candida antarctica