Preparative enantiomer separation of the inhalation anesthetics enflurane, isoflurane and desflurane by gas chromatography on a derivatized gamma-cyclodextrin stationary phase

The preparative enantiomeric separation of the inhalation anesthetics enflurane (1) and isoflurane (2) in very high chemical (>99.5%) and enantiomeric excess (ee>99%) by gas chromatography (GC) on octakis(3-O-butanoyl-2,6-di-O-n-pentyl)-gamma-cyclodextrin (4), dissolved in the apolar polysiloxane SE-54 and coated on Chromosorb P AW DMCS, is described. Up to 1 g of each enantiomer of 1-2 can been obtained per diem. The enantiomers of the highly volatile desflurane (3) can also be separated, albeit with diminished ee. The enantiomeric excess of 1-3 was checked by analytical GC on 4 and the absolute configuration of 2 and 3 has been determined via anomalous X-ray diffraction.