Asymmetric oxidation of 1,3-dithiolanes. A route to the optical resolution of carbonyl compounds

Abstract

The asymmetric oxidation ( t -BuO 2H, Ti(OPr- i ) 4, DET) of a series of 1,3-dithiolanes was carried out to produce the corresponding S-oxides with high chemical and optical yields. By contrast, the oxidation of 1,3-dithianes and 1,3-oxathiolane prepared from the same carbonyl compounds gave much lower optical yields. The optical resolution of the model ketone, dl-menthone, via a) 1,3-dithiolane formation b) asymmetric S-oxidation c) chromatographic diasteromeric separation d) regeneration of the carbonyl group, (93% optical yield), is described.