BIMETALLIC CATALYSIS - SYNTHESIS OF BENZOPHENONES THROUGH CARBONYLATION OF ARYL IODIDES CATALYZED BY FE(CO)5-CO2(CO)8 SYSTEMS

The direct, catalytic carbonylation of aryl iodides to give the corresponding benzophenones is reported for the first time. Under phase transfer conditions (aq. NaOH/C6H6/Bu4NBr) and under 1 atm pressure of carbon monoxide, iron pentacarbonyl alone promotes the conversion of iodobenzene to benzophenone and benzoic acid, whereas dicobaltoctacarbonyl alone promotes a slow carbonylation to give solely benzoic acid. A synergetic effect is observed when the reaction is carried out in the presence of catalytic amounts of both carbonyl metals, and benzophenone can be isolated in more than 50% yield. Under these conditions, o-iodotoluene affords the corresponding 2,2′-dimethylbenzophenone in 47% isolated yield. © 1990.