| Indium trichloride as a Lewis acid catalyst involved in the condensation reaction and nucleophilic substitution reaction are studied in this paper. It is divided into three parts.1. In this paper, we review the latest research and application of Indium trichloride as a catalyst in organic synthesis and classify the various types of organic reactions which indium trichloride participated as a catalyst in detail. And its possible mechanism and applications have been summarized comprehensively in the literature.2. A new method for preparation of N-tosylimines by InCl3-mediated condensation of aldehydes with p-toluenesulfonamide in refluxing benzene has been found. The reaction operation is simple and reaction condition is mild. The yields are up to 90%, but the aromatic aldehydes connecting two electron-donating groups give the desired product in only 72% yield. This is a facile method for synthesis of N-tosylimine.3. In InCl3-NaBH4-CH3CN system, the aryl terminal alkynes can undergo nucleophilic substitution with aryl-or akryl-sulfonyl chloride and convert intoα,β-unsaturated sulfones. The yields are 36-80%. In this procedure, the reaction of InCl3 with NaBH4 in CH3CN at-15℃gave HInCl2, followed by the reaction with terminal alkynes to generate vinylindium intermediate. And then the reaction of the vinylindium intermediate with aryl-or arkyl-sulfonyl chloride at room temperature affordedα,β-unsaturated sulfones. This new method has several advantages, such as mild reaction conditions, simple experimental process, highly regio-and stereoselectively.
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