Self-disproportionation of enantiomers of thalidomide and its fluorinated analogue via gravity-driven achiral chromatography: mechanistic rationale and implications

We report on the self-disproportionation of enantiomers (SDE) of non-racemic thalidomide (1) and 3′-fluorothalidomide (2) under the conditions of gravity-driven achiral silica-gel chromatography. The presence of a fluorine atom on the chiral center dramatically alters the structure and polarity of 1 and 2, resulting in the opposite SDE profile on silica-gel.