Photoinduced C-Br homolysis of 2-bromobenzophenones and Pschorr ring closure of 2-aroylaryl radicals to fluorenones.

摘要: A variety of diversely substituted 2-aroylaryl radicals, generated by photoinduced homolysis 2-bromoarylketones, is shown to undergo Pschorr cyclization yield fluorenones in moderate excellent yields. The photochemical results illustrate that the substituents two phenyl rings 2-bromobenzophenone skeleton exert a dramatic influence on reactivity derived radicals. disubstitution methoxy groups radical ring renders aryl σ-radical highly electrophilic and unreactive for hydrogen abstraction cyclization. On other hand, non-radical strongly stabilize hydrofluorenyl π-radical, formed subsequent attack ring, promote furnish isolated