名称:
Enzymatic Resolution, Desymmetrization, and Dynamic Kinetic Asymmetric Transformation of 1,3-Cycloalkanediols
摘要:
An efficient desymmetrization of cis-1,3-cyclohexanediol to (1S, 3R)-3-(acetoxy)-1-cyclohexanol ((R, S)-2a) was performed via Candida antarctica lipase B (CALB)-catalyzed transesterification, in high yield (up to 93%) and excellent enantioselectivity (ee's up to > 99.5%). (R, R)-Diacetate ((R, R)-3a) was obtained in a DYKAT process at room temperature from (1S, 3R)-3-acetoxy-1-cyclohexanol ((R, S)-2a), in a high trans/cis ratio (91: 9) and in excellent enantioselectivity of > 99%. Metal- and enzyme-catalyzed dynamic transformation of cis/trans-1,3-cyclohexanediol using PS-C gave a high diastereoselectivity for cis-diacetate (cis/trans) 97: 3). The (1R, 3S)-3-acetoxy-1-cyclohexanol (ent-(R, S)-2a) was obtained from cis-diacetate by CALB-catalyzed hydrolysis in an excellent yield (97%) and selectivity (> 99% ee). By deuterium labeling it was shown that intramolecular acyl migration does not occur in the transformation of cis-monoacetate to the cis-diacetate.