Abstract Carbonyl compounds have been successfully converted into their corresponding dithiolane, dithiane, and oxathiolane derivatives using a catalytic amount of alumina sulfuric acid (Al2O3–SO3H) with excellent yields at room temperature in short reaction times under mild conditions. This simple method is a highly chemoselective procedure for protection of aldehydes in the presence of ketones, and the heterogeneous catalyst can be recovered ...
[Jnaneshwara; Barhate; Sudalai; Deshpande; Wakharkar; Gajare; Shingare; Sukumar Journal of the Chemical Society - Perkin Transactions 1, 1998 , # 5 p. 965 - 968]