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⋅6 H2O, 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.