Synthesis, chromatographic separation, vibrational circular dichroism spectroscopy, and ab initio DFT studies of chiral thiepane tetraol derivatives.

Optically pure enantiomers of the chiral tetrahydroxythiepane derivative 3,6-dihydroxy-4,5-O-isopropylidene-thiepane (3) are obtained using a novel protocol in which a library of all possible stereoisomers of 3 is synthesized, followed by two-step stereoselective chromatography, using, first, conventional achiral and, then, chiral stationary phases. Configurational and conformational analysis of 3 are carried out using Vibrational Circular Dichroism (VCD) spectroscopy in conjunction with ab initio DFT calculations. The absolute configuration of 3 is shown to be 3R,4S,5R,6R-(+)/3S,4R,5S,6S-(-).