Synthesis of Triazafluoranthenones via Silver(I)-Mediated Nonoxidative and Oxidative Intramolecular Palladium-Catalyzed Cyclizations

Silver(I) fluoride (AgF)-mediated intramolecular nonoxidative and oxidative palladium-catalyzed cyclizations of 1,3-diphenyl- and 8-iodo-1,3-diphenylbenzo[<i>e</i>][1,2,4]triazin-7(1<i>H</i>)-ones <b>6a</b> (R = H) and <b>7a</b> (R = I) afford a new ‘alkaloid like’ ring system 2-phenyl-6<i>H</i>-[1,2,4]triazino[5,6,1-<i>jk</i>]carbazol-6-one <b>8a</b> (triazafluoranthenone) in 86 and 100% yields, respectively. Furthermore, these cyclization protocols were used to prepare triazafluoranthenone analogues <b>8b</b>–<b>e</b> bearing dialkylamino, methoxy, and phenylsulfanyl substituents at C-5, which were also independently synthesized from triazafluoranthenone <b>8a</b> by regioselective nucleophilic addition. Similar AgF-mediated intramolecular nonoxidative and oxidative palladium-catalyzed cyclizations of 8,10-dihydro-1-iodo-10-phenylphenazin-2(7<i>H</i>)-ones <b>13</b> gave the new ‘alkaloid like’ ring system 8<i>H</i>-indolo[1,2,3-<i>mn</i>]phenazin-8-one <b>14</b> in 80 and 18% yields, respectively.