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

An iodine-mediated cyclization has been developed to 4-aryl--1,2,3-triazoles, with -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 -1,2,3-triazoles.