PAPER	Synthesis 2007: 551-557   DOI: 10.1055/s-2007-965889
© Georg Thieme Verlag Stuttgart · New York
Iodobenzene Dichloride as a Stoichiometric Oxidant for the Conversion of Alcohols into Carbonyl Compounds; Two Facile Methods for Its Preparation
Xue-Fei Zhao, Chi Zhang*
The State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. of China Fax: +86(22)23499247; e-Mail: zhangchi@nankai.edu.cn;
Received 15 September 2006

Abstract

A highly efficient and mild procedure is described for the oxidation of different types of alcohols using 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO) as the catalyst, iodobenzene dichloride (PhICl₂) as a stoichiometric oxidant, and pyridine as the base. This procedure also smoothly oxidizes 1,2-diols to α-hydroxy ketones or α-diketones depending upon the amount of iodobenzene dichloride used. A competitive study shows that using the 2,2,6,6-tetramethylpiperidin-1-yloxy/iodobenzene dichloride/pyridine system aliphatic secondary alcohols are preferentially oxidized over aliphatic primary alcohols. In addition, two very convenient and high yielding procedures for the preparation of iodoarene dichlorides from iodoarenes have been developed. One employs solid sodium chlorite as a chlorinating agent in dilute hydrochloric acid solution; the other uses sodium hypochlorite as a chlorinating agent still in hydrochloric acid solution, which is more robust than the sodium chlorite system. Typically, the preparation of iodobenzene dichloride from iodobenzene was performed in five minutes using the sodium hypochlorite/hydrochloric acid system.

Key words

iodobenzene dichloride - alcohols - catalysis - TEMPO - oxidation