Determination of absolute configurations and predominant conformations of general inhalation anesthetics: desflurane

Although the mechanism of anesthetic action is not yet clearly understood, it was recently shown that the pure enantiomers of chiral inhalation anesthetic agents interact differentially with the ion channels in the central nervous system. This differential interaction was suggested to arise from stereospecific binding of chiral enantiomers to proteins. To understand and model the differential nature of binding of enantiomers it is necessary to determine their absolute configurations and the number of predominant conformers. From studies on circular dichroism in the vibrational transitions of desflurane (CF2HOCHFCF3), we found that (-)-desflurane has the (R)-configuration and (+)-desflurane has the (S)-configuration [corrected]. In addition, each enantiomer existed in two distinct conformations at room temperature.