Synlett 2005(1): 173-175  
DOI: 10.1055/s-2004-836047
LETTER
© Georg Thieme Verlag Stuttgart · New York

A New and Efficient Transition Metal-Free Oxidation of Secondary Alcohols to Ketones Using Aqueous HBr and H2O2

Vishal B. Sharma, Suman L. Jain, Bir Sain*
Chemical and Biotechnology Division, Indian Institute of Petroleum, Dehradun-248005, India
e-Mail: birsain@iip.res.in;
Further Information

Publication History

Received 24 August 2004
Publication Date:
29 November 2004 (online)

Abstract

Aqueous HBr/H2O2 was found to be an efficient and green system for the oxidation of secondary alcohols in excellent yields under very mild conditions.

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General Experimental Procedure: To a stirred solution of secondary alcohol (1 mmol) and 30% H2O2 (2 mmol) in MeCN (5 mL) was added drop wise aq 48% HBr (20 mol%) and the reaction mixture was refluxed for the time as given in Table [1] . The progress of the reaction was monitored by TLC (SiO2). At the end of reaction the excess H2O2 was destroyed by the addition of aq bisulfite followed by the filtration through a small Buchner funnel. After filtration, the reaction mixture was purified by the solvent extraction with CH2Cl2 (3 times) and the solvent was evaporated under vacuum. The residue thus obtained was purified by column chromatography on silica gel using EtOAc-hexane (1:4) as eluent. Evaporation of the solvent yielded corresponding ketones. The reaction times and yields of the products are presented in the Table [1] . The products were identified by comparing their physical and spectral data with those of authentic compounds reported in literature.