Synthesis of aryl esters using carboxylic acids, triarylphosphites, and N-iodosuccinimide†

The direct synthesis of aryl esters from carboxylic acids has been achieved by using triarylphosphites and N-iodosuccinimide in chlorobenzene under neutral reaction conditions. This straight-forward green esterification method provides the desired aryl esters in good to high yields (42 to 99% yield) and a wide range of aromatic and aliphatic carboxylic acids can serve as substrates in this esterification reaction. For more acidic acids, the addition of DBU enhances the reaction yields. A radical mechanism, supported by the results of a radical trapping experiment and ³¹P NMR studies, was proposed to explain the reaction outcome.