Synlett 2002(9): 1505-1507
DOI: 10.1055/s-2002-33519
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Novel, Efficient, and Highly Selective O-Bn Bond Cleavage Reaction via a Rare K-Induced Electron Transfer Process

Lei Shi, Wu Jiong Xia, Fu Min Zhang, Yong Qiang Tu*
Department of Chemistry & National Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
Fax: +86(931)8912582; e-Mail: tuyq@lzu.edu.cn;
Further Information

Publication History

Received 4 June 2002
Publication Date:
17 September 2002 (online)

Abstract

A new, efficient and highly selective deprotective method of both benzyl and benzylidene groups for protection of monohydroxyl and dihydroxyl, respectively, has been developed by using the system K-t-BuNH2-t-BuOH-18-crown-6. This method is valuable since it can not only selectively protect the TBDMS and THP groups and the ethylene ketal from cleavage, but also keep the separate or conjugated C=C bonds from reduction. A possible electron transfer reaction process was also suggested.

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One equiv of substrate dissolved in dried THF was sequentially added to two equiv of dry t-BuNH2 and two equiv of t-BuOH and 10 equiv of potassium and 0.1 equiv of 18-crown-6. The mixture was stirred at r.t. for 1-6 h (the starting material disappeared, checked with TLC), workup as the general procedure to afford the corresponding alcohols in 73-99% yield.