ISSN:
0899-0042
Keywords:
enzymic kinetic resolution
;
porcine pancreatic lipase (PPL)
;
hydrolysis
;
transesterification
;
acylation
;
enol esters
;
chiral HPLC
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Both hitherto unknown (+)-(R)- and (-)-(S)-thioglycidyl esters, (R)-(2) and (S)-(2), have been synthesized with different high enantiomeric excesses (ee) by two routes from the corresponding rac-glycidyl esters rac-(1). The first includes a porcine pancreatic lipase (PPL)-mediated kinetic resolution of these esters followed by sulfuration with practically complete inversion to the (+)-(R)-enantiomer (+)-(R)-(2) (36-86% ee). (-)-(S)-Thioglycidyl esters (-)-(S)-(2) are obtained by the reverse reaction sequence (43-80% ee). In the latter case the hydrolysis rate is lower than that of analogous glycidyl esters. Moreover, the dependence of enantiomeric excess on the size of the acyl-group is of the opposite tendency. Therefore, in both cases suitable selection of the acid residue gives rise to maximum enantioselectivity. The irreversible lipase-catalyzed acylation of rac-glycidol and rac-thioglycidol, however, was found to be a less suitable alternative. The enantiomeric excess of recovered homochiral esters was determined by chiral chromatography using modified cellulose stationary phases (OB, OD). © 1993 Wiley-Liss, Inc.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chir.530050412
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