A useful and convenient synthetic protocol for interconversion of carbonyl compounds to the corresponding 1,3-oxathiolanes and vice versa employing organic ammonium tribromide (OATB)

A wide variety of carbonyl compounds 1 can be easily protected selectively as the corresponding 1,3-oxathiolanes 2 in good yields using a catalytic amount (0.01–0.1 equiv.) of n-tetrabutylammonium tribromide in dry CH2Cl2 at 0–5 °C. On the other hand, various 1,3-oxathiolanes 2 can be deprotected chemoselectively to the parent carbonyl compounds 1 employing 0.5 equivalents of organic ammonium tribromides under identical conditions in very high yields. Mild conditions, high selectivity and yield, highly efficient, less expensive, and no brominations either at the double bond or allylic position and even α- to the keto position or aromatic ring are some of the major advantages of the protocol.