Gas chromatographic enantiomer separation of C-3 and C-4 synthons: Prediction of absolute configuration from elution order and enzymatic resolution

Enantiomers of C-3 secondary alcohols, 3-hydroxybutanoates, and cyclic 1,3- dithioacetals were separated by chiral GLC using CP-Chirasil-Dex CB and Chi raldex G-TA columns. The former was most successful for analysis of n-alkyl esters of secondary alcohols and the separation depended on the chain leng th of the acyl group and the electronic and steric properties of the other substituents. The Chiraldex G-TA column was efficient for analysis of secon dary alcohols, derivatized as their trifluoroacetates. The elution order of the secondary alcohols and the corresponding acetates was always the same with respect to the size of groups connected to the stereocenter. However, when the secondary alcohols were analyzed as their trimethylsilyl derivativ es, the elution order was reversed. Elution order on chiral columns and ena ntiomeric ratios, E-values, obtained in kinetic resolutions catalyzed by li pase B from Candida antarctica (CALB) were evaluated as a method for predic tion of absolute configuration. The usefulness of the method was demonstrat ed using 22 pairs of enantiomers. Chirality 11:760-767 1999. (C) 1999 Wiley -Liss, Inc.