p-Toluenesulfonic acid adorned on MCM-41: an efficient and mild catalyst for the regio/chemo-selective hydrolysis of terminal isopropylidene acetals

Regio/chemo-selective hydrolysis of a 5,6-O-isopropylidene group over a 1,2-O-isopropylidene group is accomplished to obtain corresponding diols in good to excellent yields within 4-5 hours using the p-toluenesulfonic acid impregnated MCM-41 (PTSA-MCM-41) catalyst in acetonitrile and water (9:1, v/v) at room temperature. Other sensitive hydroxyl protecting groups such as naphthyl, toluoyl, pivaloyl, benzoyl, and benzyl are compatible with this methodology. The low cost of the PTSA-MCM-41 catalyst and ease of separation of product from the reaction mixture are significant advantages of this method, which makes it useful in the multigram scale operation.