摘要:
To date, the enzyme-catalyzed kinetic resolution of the secondary alcohol [Ar-C*H(CH3)OH, Ar = 2,4,6'-triisopropylphenyl] has not been available, due to high steric hindrance around the hydroxy group. To achieve resolution, the reaction site was extended by the introduction of two kinds of spacers, [-C(=O)CH2-] and [-C(=O)C**HCN-]. In the first substrate, the recognition of remote chirality [Ar-C*H(CH3)O-C(=O)CH2-OH] by acylation with Burkholderia cepacia lipase was examined by changing reaction conditions and acyl donors. An E = 22 in the preference of (1'R)-isomer, was recorded with vinyl acetate as an acyl donor at 25 degrees C. In the second substrate, there was a matched enantiomeric pair [stereoselective ratio at C-1' = 15, in the preference of (1'R)-isomer] and a mismatched pair [stereoselective ratio at C-1' = 2.5, in the preference of (1'S)-isomer] based on the relative stereochemistry between the two chiral centers [Ar-C*H(CH3)O-C(=O)C**HCN-OH]. (c) 2012 Elsevier B.V. All rights reserved.