Transition Metal Catalyst-Free and Radical Initiator-Free Carbonylation of Aryl Iodides

Transition metal catalyst-free and radical initiator-free carbonylation processes for producing aryl esters, carboxylic acids, or carboxylic acid anhydrides in excellent yields were developed. Aryl iodides (Ar-I) react with CO and alkali metal aryloxides (Ar-1-OM: M = alkali metal), water and bases, or alkali metal salts of aromatic carboxylic acids (Ar-COOM) for 2 h to produce the corresponding aryl esters (Ar-COOAr1), carboxylic acids (Ar-COOH), or carboxylic acid anhydrides [(Ar-CO)(2)O] almost quantitatively. These processes use only heating of 250-270 degrees C and do not require any transition metal catalysts or any radical initiators and additives (e.g t-BuOK, and 1,10-phenanthroline), which are indispensable in the hitherto carbonylation processes. Because of the high yields and no use of any reagents other than the reactants, the desired products can be easily obtained by a simple separation step (e.g., filtration) of the by-produced alkali metal iodides (MI). These reactions probably proceed via radical mechanism in accordance with single electron transfer.