Copper(II) Chloride Dihydrate: A Catalytic Agent for the Deprotection of Tetrahydropyranyl Ethers (THP Ethers) and 1-Ethoxyethyl Ethers (EE Ethers)

Tetrahydropyranyl ethers (THP groups) and 1-ethoxyethyl ethers (EE groups) are removed upon refluxing in 95% EtOH or Me2CO–H2O (95:5) in the presence of a catalytic amount of copper(II) chloride dihydrate (2–5 mol%).