Recent Advances in the Denitrogenative Annulation Reactions of 1,2,3-Thiadiazoles

1,2,3-Thiadiazoles exhibit versatile reactivity due to their ability to undergo ring cleavage, forming alpha-diazothione species through a Dimroth-type equilibrium. Denitrogenation of the alpha-diazothione, induced by high temperature, irradiation, or strong bases, allows generation of a wide range of reactive intermediates. Since 2016, the transition-metal-catalyzed denitrogenative transannulation of 1,2,3-thiadiazoles has garnered significant attention as a promising approach to constructing diverse heterocyclic scaffolds. This review focuses on the denitrogenative reactions of 1,2,3-thiadiazoles, particularly highlighting the novel rhodium-catalyzed denitrogenative transannulation transformations along with their mechanisms. The denitrogenative annulation of 1,2,3-thiadiazoles has emerged as an important strategy in organic synthesis, as it can permit streamlined access to a variety of functionalised heterocyclic compounds from a common, stable building. This review focuses on the denitrogenative reactions of 1,2,3-thiadiazoles, particularly focused on novel rhodium-catalyzed methodology. image