PROCESS FOR PREPARING (-)MENTHOL AND SIMILAR COMPOUNDS

摘要

A process of separating a single desired stereoisomer from a racemic mixture of eight stereoisomers of a compound of formula (III), wherein R1 represents an isopropanol group, an isopropyl group or an isopropylene group, includes the steps of: contacting the racemic mixture in a suitable organic solvent with an esterifying agent and a stereospecific enzyme which stereoselectively esterifies the -OH group of the desired stereoisomer, for a time sufficient to convert a desired percentage of the desired stereoisomer to a compound of formula (IV), wherein R1 is as defined above and R4 is an alkyl or an aryl group, to give a first reaction product including the compound of formula (IV), the organic solvent, the unconverted stereoisomers of the compound of formula (III), excess esterifying agent and by-products of the reaction; and separating the compound of formula (IV) from the first reaction product. The process is of particular application for the production of (-)-menthol.