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Synthesis 2019; 51(04): 944-952
DOI: 10.1055/s-0037-1610307
paper
© Georg Thieme Verlag Stuttgart · New York

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
› Author Affiliations
This work was supported by the National Natural Science Foundation of China (21562021), the Natural Science Foundation (20143ACB21014), the Fellowship for Young Scientists program (2015BCB23009), and the Sci & Tech Project of the Department of Education (GJJ160763) of Jiangxi Province.
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Publication History

Received: 15 August 2018

Accepted after revision: 21 September 2018

Publication Date:
17 October 2018 (online)

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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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    Supporting information for this article is available online at https://doi.org/10.1055/s-0037-1610307.
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