Synthesis of Polysubstituted Cyclopentene and Cyclopenta[ b]carbazole Analogues from Unsymmetrical 4-Arylidene-3,6-diarylhex-2-en-5-ynal and Indole Derivatives via an Iodine Mediated Electrocyclization Reaction

Azide-free cyclization reaction access to 4-aryl-NH-1,2,3-triazoles: P-toluenesulfonyl hydrazide and sulfamic acid as nitrogen sources

An iodine-mediated cyclization has been developed to 4-aryl-NH-1,2,3-triazoles, with p-toluenesulfonyl hydrazide and sulfamic acid used as nitrogen sources. Sulfamic acid plays a crucial role in this reaction by both acting as a substrate and providing an acidic environment. This reaction offers a metal- and azide-free strategy to access NH-1,2,3-triazoles.

Iodine-Catalyzed Regioselective Synthesis of Diphenyl-Substituted Carbazoles via [4 + 2] Annulation of β-Formyl Ketones with Indoles

The [4 + 2] annulation of β-formyl ketones with an indole has been developed for the regioselective synthesis of diphenyl-substituted carbazoles in the presence of a catalytic amount of iodine. The 1,4-dicarbonyl compound containing a phenyl group at the α-position of an aldehyde group reacts more readily with indoles to form carbazole derivatives. Using this method, a variety of carbazole derivatives can be readily accessed under mild reaction conditions.

Iodine-Catalyzed Annulation Reaction of Ortho-Formylarylketones with Indoles: A General Strategy for the Synthesis of Indolylbenzo[b]carbazoles

The iodine-catalyzed cascade reaction of ortho-formylarylketones with indoles for the synthesis of indolylbenzo[b]carbazoles is reported. The reaction is initiated in the presence of iodine by two successive nucleophilic additions of indoles with an aldehyde group of ortho-formylarylketones, and the ketone does not undergo a nucleophilic addition and only involves in the Friedel-Crafts-type cyclization. A variety of substrates are tested, and the efficiency of this reaction is demonstrated with gram-scale reactions.