Preparative chiral liquid chromatography for enantiomeric separation of pheromones.

Cellulose triacetate was investigated as a chiral stationary phase for preparatively separating the enantiomers of lineatin, frontalin, exo-brevicomin, endo-brevicomin, verbenone, (E)-conophthorin, and grandisol. Tens of milligrams of both enantiomers were efficiently prepared in high percentage enantiomeric excess from one injection of each compound except grandisol. We prepared grandisyl acetate, benzoate, and 4-bromobenzoate to determine if derivatization of the free alcohol might improve separation. Of these, grandisyl 4-bromobenzoate provided the best separation but was still not very well resolved. Preparative separation of enantiomers on cellulose triacetate is a viable alternative to stereoselective synthesis when semiochemicals of very high enantiomeric purity are required for biological testing.