Reactions of aryl ketones and coumarins with iodine(ih) tris(trifluoroacetate)

Abstract

The reaction of acetophenones with iodine(III) tris(trifluoroacetate) yields 3'- and/or 2-iodo derivatives, depending upon the substituent on the aromatic ring and the reaction conditions. The reaction was examined by changing the molar ratio of acetophenone versus the reagent, reaction temperature, and solvent. In similar reactions flavanones and coumarins gave iodo derivatives in which iodine is incorporated at various positions orientated by the oxygen functions. 1 ,2-Diphenylethanone yields 2-hydroxy-2-(2-iodophenyl)-l -plienylethanone and 1 -(2-iodophenyl)-2-phenylethanedione. The reactions of other aromatic ketones such as 9-xanthenone, 9-fluorenone, and anthrone also give iodo derivatives in moderate to good yields. The mechanisms for the iodination at the t-carbon to the carbonyl group have been discussed. © 1987 The Chemical Society of Japan.