Synlett 2017; 28(03): 381-385
DOI: 10.1055/s-0036-1588350
letter
© Georg Thieme Verlag Stuttgart · New York

KHF2: A Mild and Selective Desilylating Agent for Phenol tert-Butyldimethylsilyl (TBDMS) Ethers

Mahesh K. Lakshman*
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
b  The PhD Program in Chemistry, The City University of New York, New York, NY 10016, USA
,
Fatou A. Tine
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
,
Tashrique A. Khandaker
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
,
Vikram Basava
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
,
Nana B. Agyemang
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
,
Michael S. A. Benavidez
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
,
Marikone Gaši
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
,
Lisa Guerrera
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
,
Barbara Zajc*
a  Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA   Email: mlakshman@ccny.cuny.edu   Email: bzajc@ccny.cuny.edu
b  The PhD Program in Chemistry, The City University of New York, New York, NY 10016, USA
› Author Affiliations
Further Information

Publication History

Received: 13 October 2016

Accepted after revision: 19 October 2016

Publication Date:
17 November 2016 (online)


Undergraduate research participants
§ Equal contributions from these authors

Abstract

TBDMS (t-BuMe2Si, tert-butyldimethylsilyl) ethers of a variety of phenols have been deprotected with KHF2 in MeOH, at room temperature. Carboxylic ester and labile phenolic acetate were unaffected under these conditions. In competition reactions between TBDMS ethers of a phenol and two primary benzylic alcohols, the phenolic ether underwent cleavage whereas the alcohol ethers remained intact. From a substrate containing both a phenolic hydroxyl group and a secondary, doubly benzylic hydroxyl group protected as TBDMS ethers, the phenol was rapidly and selectively released. Cleavage of TBDMS, TBDPS, and TIPS ethers of a phenol was also compared. TBDMS and TBDPS ethers underwent cleavage at room temperature within 30 minutes, whereas removal of the TIPS ether required 2.5 hours. Ease of cleavage appears to be TBDMS ≈ TBDPS > TIPS. At 60 °C, TBDMS ethers of primary benzylic, allylic, and unactivated alcohols can be efficiently desilylated over a prolonged period (13–17 h). Thus, KHF2 proves to be a mild and effective reagent for the selective desilylation of phenol TBDMS ethers at room temperature.

Supporting Information

 
  • References and Notes

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  • 32 Comparison based upon catalogue prices of a leading chemicals supplier.