Hunsdiecker-type bromodecarboxylation of carboxylic acids with iodosobenzene diacetate-bromine

Carboxylic acids are bromodecarboxylated in moderate to good yields on reac tion with iodosobenzene diacetate and bromine under irradiation with a tung sten lamp. The reaction works very well with carboxylic acids having a prim ary, secondary or tertiary alpha-carbon atom, although diphenylacetic acid gives benzophenone. Benzoic acid derivatives are bromodecarboxylated in mod erate yields if electron-withdrawing substituents are present in the benzen e ring, while they are recovered mostly unchanged if the substituents are e lectron-donating. Partially iodinated products have been isolated in low yi eld from the bis-bromodecarboxylation of dicarboxylic acids having two brid gehead or-carbon atoms. (C) 2000 Elsevier Science Ltd. All rights reserved.