Conversion of a racemate into a single enantiomer in one step by chiral liquid chromatography: Studies with rac ‐2,2′‐diiodobiphenyl

The enantiomers of rac ‐2,2′‐diiodobiphenyl were separated by liquid chromatography on microcrystalline triacetylcellulose. The conformational lability, a large separation factor α, and a suitable capacity factor k ′(+) of this biphenyl allowed us to convert the racemate into 90% of enantiomerically pure (‐)‐2,2′‐diiodobiphenyl and 10% of pure (+)‐2,2′‐diiodobiphenyl, respectively, by a series of in situ racemization‐elution cycles. The much better retained (+)‐enantiomer was racemized on the chromatographic column at 50°C after the less retained (‐)‐enantiomer has already been eluted at 8°C. © 1995 Wiley‐Liss, Inc.