introduction of sulfonated rice husk ash as a highly efficient reusable catalyst for the protection of the hydroxyl group

a mild, efficient and fast method for the trimethylsilyl (tms), tetrahydropyranyl (thp) and methoxymethyl (mom) protection of alcohols and phenols in the presence of sulfonated rice husk ash (rha-so3h) is reported. all reactions were performed at room temperature in high to excellent yields. all the products are separated and compared with authentic samples and/ or identified using different types of methods including ft-ir, 1h nmr and 13c nmr spectroscopy. ease of the preparation and handling of the catalyst, heterogeneous reaction conditions, reusability of the catalyst, easy work-up procedure and short reaction times are the main advantages of this method, which make this procedure useful and attractive addition to the available methods.