Lipase-Catalyzed Kinetic Resolution of Aryltrimethylsilyl Chiral Alcohols

Abstract

Lipase-catalyzed kinetic resolution of aryltrimethylsilyl chiral alcohols through a transesterification reaction was studied. The optimal conditions found for the kinetic resolution of m- and p-aryltrimethylsilyl chiral alcohols, led to excellent results, high conversions (c = 50%), high enantiomeric ratios (E > 200) and enantiomeric excesses for the remaining (S)-alcohol and (R)-acetylated product (>99%). However, kinetic resolution of o-aryltrimethylsilyl chiral alcohols did not occur under the same conditions applied to the other isomers.

Candida antarctica lipase‐B‐catalyzed kinetic resolution of 1,3‐dialkyl‐3‐hydroxymethyl oxindoles

“…Initially, kinetic resolution of racemic 1,3‐dibenzyl‐3‐(hydroxymethyl)indolin‐2‐one ( 1a , 0.1 mmol, 34.3 mg), catalyzed by B . cepacia 69 (Lipase PS‐C, 50 mg) was investigated using vinyl acetate (0.5 mL) both as acyl donor and solvent at room temperature. The reaction was stopped after 21 h, the evaluation of the crude reaction mixture on chiral HPLC showed the conversion to be 9%, and the acylated product 3a was found to have 89% enantiomeric excess ( ee ), whereas the unreacted substrate 1a was found to have 11% ee .…”