Ravid, U., Institute of Field Crops, Agricultural Research Organization, Newe Ya'ar Research Center, Haifa, 31-900, Israel
Putievsky, E., Institute of Field Crops, Agricultural Research Organization, Newe Ya'ar Research Center, Haifa, 31-900, Israel
Katzir, I., Institute of Field Crops, Agricultural Research Organization, Newe Ya'ar Research Center, Haifa, 31-900, Israel

Direct separation of the enantiomers of the two diastereomers, menthone and isomenthone, was performed using an octakis‐(3‐O‐butyryl‐2,6‐di‐O‐pentyl)‐α‐cyclodextrin phase. Enantiomerically pure (—)‐menthone and (+)‐isomenthone were detected in many oils of Mentha, Micromeria fruticosa (L.) Druce and Calamintha incána (Sm.) Heldr. High enantiomeric purities of (+)‐menthone and (—)‐isomenthone were detected in commercial and freshly distilled geranium oils. Copyright © 1994 John Wiley & Sons, Ltd