Ruthenium(II)-bipyridine anchored montmorillonite-catalyzed oxidation of aromatic alkenes with tert-butyl hydroperoxide

Bipyridylsilylated montmorillonite (abbreviated as bpy-mont) is prepared from H-montmorillonite and 6-(ethoxydimethylsilyl)-2,2'-bipyridine. Treatment of the bpy-mont with [RuCl2(CO)2], affords a novel clay catalyst including Ru(II)-bpy. The oxidation of aromatic alkenes with tert-BuOOH in the presence of the catalyst and Et3N mainly produces vic-bis(tert-butyldioxy)alkanes. A similar oxidation of 2,3-dimethyl-1,3-butadiene affords 1,4- and 1,2-bis(tert-butyldioxy)alkenes. In the absence of Et3N the oxidation of 1,1-diphenylethylene gives 2-tert-butyldioxy-1-hydrodioxy-1,1-diphenylethane as a major product. This catalyst is easily separated after the reactions and can be reused for oxidation. (C) 1998 Elsevier Science Ltd. All rights reserved.