Coupling hydroxy iodo benzene

Oxidation of N-aromatic methanesulfonamides 321 with (diacetoxyiodo)benzene in the presence of thiophene in trifluoroethanol or hexafluoroisopropanol (HFIP) affords the respective coupling products 322 in good yield (Scheme 3.131) [380]. The head-to-tail thiophene dimers 324 can be selectively prepared by the hypervalent iodine oxidation of 3-substituted thiophenes 323 [381,382] and bipyrroles 326 can be regios-electively synthesized by oxidative dimerization of pyrroles 325 with [bis(trifluoroacetoxy)iodo]benzene in the presence of bromotrimethylsilane [383]. Likewise, bithiophenes 328 have been synthesized from 3,4-disubstituted thiophenes 327 using [hydroxy(tosyloxy)iodo]benzene in the presence of bromotrimethylsilane in hexafluoroisopropanol [384]. 

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