Syntheses of (R)- and (S)-enantiomeric 1,1,1-trifluoromethyl-2-alkanols with high enantiomeric purity controlled through derivatization with L-menthyl phthalate

摘要

Readily available L-menthyl phthalate has been shown to be an effective derivatizing agent for determination of the enantiomeric purity of alkyl- and aryl-substituted 1,1,1-trifluoromethyl-2-alkanols using HPLC and GC. It has been shown that a previously described protocol for one-step enzymatic kinetic resolution results in the formation of the desired 1,1,1-trifluoromethyl-2-alkanols with 96-98% ee. Enrichment of the (R)-isomer of trifluoromethyl alkanols by repetition of the enzymatic hydrolysis procedure was found to increase the ee up to 99.9%. Furthermore, excessive conversion of the corresponding esters during enzymatic hydrolysis allowed enantiomerically pure (S)-1,1,1-trifluoromethyl-2-alkanols to be obtained. (C) 2015 Elsevier Ltd. All rights reserved.