Bismuth(III) nitrate pentahydrate: a stoichiometric reagent for microwave induced mild and highly efficient aerial oxidation of aromatic aldehydes under solvent-free conditions

Aromatic aldehydes possessing a wide variety of substituents were smoothly converted to carboxylic acids in excellent yields by stoichiometric bismuth(III) nitrate pentahydrate in presence of aerial oxygen in a microwave-oven under solvent-free conditions. The method is environmentally benign being solvent-free, operationally simple, highly chemoselective, employing no cumbersome work-up procedures, having wide general applicability, short reaction times, mild reaction conditions, large scale-ups and very good yields.