Reactivity in the formation of lactones from aromatic carboxylic acids with organohypervalent iodine compounds in the Suárez system

Abstract

The reactivity of various iodanes, such as (diacetoxyiodo)arenes, the Dess–Martin reagent, and (arylsulfonyloxy)benziodoxolones, with (o-alkyl)- and (o-phenyl)arenecarboxylic acids in the presence of iodine (Suárez system) was studied to give the corresponding lactones via oxygen-centered radicals. (Diacetoxyiodo)arenes gave the lactones in good yields, while 1-(arylsulfonyloxy)benziodoxolones gave lactones together with the iodinated lactones. The Dess–Martin reagent also showed the same reactivity as (diacetoxyiodo)arenes to give the lactones. Among them, (diacetoxyiodo)toluene showed the best reactivity for the conversion of these carboxylic acids to the corresponding lactones.