Selective cleavage of ethers using silica-alumina gel catalysts prepared by the sol-gel method

The selective cleavage of tetrahydropyranyl (THP), methoxymethyl (MOM), 1-ethoxyethyl (EE), 1-methyl-1-methoxyerhyl (MME) and trimethylsilyl (TMS) ether groups with silica-alumina gels prepared by the sol-gel method has been investigated The deprotection rate follows the order: TMS > MME >> EE > THP >> MOM. The selective deprotection of diol derivatives with mixed protecting groups was achieved efficiently. Bis-THP and bis-MOM ether derivatives of a substrate which contained a primary and a tertiary hydroxyl groups were mono-deprotected with moderate selectivity. The selective deprotection of glycerol ethers was also examined. The silica-alumina gels prepared by the sol-gel method are thus shown to be a good catalyst for selective cleavage of ether protecting groups giving the product in a simple manner under mild conditions. Copyright (C) 1996 Published by Elsevier Science Ltd