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

doi:10.1055/s-0037-1610307

Synthesis, Table of Contents

Synthesis 2019; 51(04): 944-952
DOI: 10.1055/s-0037-1610307

paper

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*

Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Avenue, Nanchang, Jiangxi 330013, P. R. of China Email: gongshanshan@jxstnu.edu.cn Email: sunqi@jxstnu.edu.cn

,

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: gongshanshan@jxstnu.edu.cn Email: sunqi@jxstnu.edu.cn

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Abstract

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Abstract

As a Group IVB transition metal Lewis acid, hafnium triflate [Hf(OTf)₄] exhibited 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 are significantly different, ranging from 0.05 mol% to 3 mol%, regioselective deprotection of TBS could be easily implemented. Moreover, chemoselective cleavage of different silyl ethers or removal of TBS in the presence of most hydroxyl protecting groups was also accomplished. NMR analyses of silyl products from TBS deprotection indicated that Hf(OTf)₄-catalyzed desilylation may proceed via different mechanisms, depending on the solvent used.

Key words

hafnium triflate - desilylation - regioselectivity - chemoselectivity - mechanism

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References

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Supporting Information

Hafnium Triflate as a Highly Potent Catalyst for Regio- and Chemoselective­ Deprotection of Silyl Ethers

Hafnium Triflate as a Highly Potent Catalyst for Regio- and Chemoselective Deprotection of Silyl Ethers