A highly efficient procedure for regeneration of carbonyl groups from their corresponding oxathioacetals and dithioacetals using sodium nitrite and acetyl chloride in dichloromethane

A wide variety of oxathioacetals 1 as well as dithioacetals 2 can be chemoselectively deprotected to the corresponding carbonyl compounds 3 in good yields by employing NaNO2-AcCl and H2O in CH2Cl2 at 0 degreesC to room temperature. Some of the major advantages of this procedure are: mild conditions, easy to handle, highly chemoselective and efficient, high yields and inexpensive reagents. In addition, no acetylation occurs at the hydroxyl group nor chlorination takes place at the double bond.