Simple and efficient deprotection of 1,3-dithianes and 1,3-dithiolanes by copper(II) salts under solvent-free conditions

Aerobic solid state deprotection of 1,3-dithianes and 1,3-dithiolanes of aromatic and aliphatic aldehydes and ketones has been performed in excellent yields by Cu(NO3)2·2.5H2O in the presence of montmorillonite K10 clay and sonic waves at room temperature. These dethioacetalizations proceed more slowly but efficiently under catalytic conditions by using 20% of the copper(II) salt with K10 clay and sonication.