Iron-Catalyzed Oxidative Cleavage of Olefins and Alkynes to Carboxylic Acids with Aqueous tert-Butyl Hydroperoxide

A new method for the oxidation of aromatic olefins and alkynes has been developed using inexpensive iron(III) chloride hexahydrate (FeCl3 center dot 6H(2)O, 5 mol%) catalyst in combination with commercially available aqueous 70% tert-butyl hydroperoxide (TBHP) as oxidant. The present system works well for aromatic alkenes and alkynes with both electron-donating and electron-withdrawing substituents being tolerated. The protocol is free from chromatographic purification and the carboxylic acids are obtained in high yields by simple filtration.