Deprotection of t-Butyldimethylsiloxy (TBDMS) Protecting Group with Catalytic Copper (II) Chloride Dihydrate

The protection of functional group is unavoidable in multi-step organic synthesis. Along with tetrahydropyranyl (THP) ethers, t-butyldimethylsilyl (TBDMS) ethers have been widely used for protecting hydroxyl groups. TBDMS ether is more stable to hydrolysis than trimethylsilyl ether, but is still readily cleaved by a variety of selective conditions. The deprotection of TBDMS is usually under mild acidic conditions [AcOH/H2O/THF, 3:1:1, or BF3 Et2O/CHCl3, etc. ], or with a fluoride ion. Although those deprotection conditions have been widely applied in organic synthesis, there is still a need to look for alternative and milder condition for the deprotection of TBDMS ethers. We have recently reported that catalytic amount of cheap and readily available copper (II) chloride dihydrate (CuCl2 2H2O) can efficiently cleave THP ethers. In this communication, we further describe the successful removal of TBDMS ether by CuCl2 2H2O under catalytic condition (Scheme 1).