Hafnium Triflate as a Highly Potent Catalyst for Regio- and Chemoselective Deprotection of Silyl Ethers
Xiu-An Zheng, Rui Kong, Hua-Shan Huang, Jing-Ying Wei, Ji-Zong Chen, Shan-Shan Gong*, Qi Sun*
*Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Avenue, Nanchang, Jiangxi 330013, P. R. of China, Email: gongshanshanjxstnu.edu.cn, sunqijxstnu.edu.cn
X.-A. Zheng, R. Kong, H.-S. Huang, J.-Y. Wei, J.-Z. Chen, S.-S. Gong, Q. Sin, Synthesis, 2019, 51, 944-952.
Hf(OTf)4 exhibits exceptionally high potency in desilylations. Since the amounts of Hf(OTf)4 required for the deprotection of 1°, 2°, 3° alkyl and aryl tert-butyldimethylsilyl (TBS) ethers range from 0.05 mol% to 3 mol%, a regioselective deprotection can be achieved. A chemoselective cleavage of different silyl ethers or removal of TBS in the presence of most hydroxyl protecting groups was also accomplished.
see article for more examples