Synthesis Of Benzothiazonine By Rhodium-catalyzed Denitrogenative Transannulation Of 1-sulfonyl-1,2,3-triazole And Thiochromone

1-Sulfonyl-1,2,3-triazoles have emerged as an efficient source for the synthesis of nitrogen containing compounds through in situ generation ofα-diazoimine.This document focuses on the construction of medium-size N,S-heterocycles which has an important role in pharmaceutics and drug discovery.This procedure involving ring expansion can be made possible through a[6+3]cyclization reaction of 1,2,3-triazole with thiochromone to afford some medium N,S-heterocycles including benzothiazonine derivatives.On the basis of various experiments and investigations,it was found that when 1-Sulfonyl-1,2,3-triazole was treated with 5 mol%Rh₂（OAc）₄ as catalyst under a nitrogen atmosphere and temperature of90 ^oC with toluene as solvent afforded the product at an almost quantitative yield.The development of synthetic methods for such a novel compound is of great significance in the field of synthetic organic chemistry and drugs discovery,owing to the fact that it involves the construction of a more challenging 9-membered ring containing sulfur and nitrogen atoms.Under the standard conditions,we successfully achieved the reaction of1-sulfonyl-1,2,3-triazole with Thiochromone through intermolecular sulfur ylide formation followed by ring expansion to enable the construction of renaissance 9-membered N,S-heterocycles.The products could also be converted to some other derivatives containing medium-size N,S-heterocycles,illustrating the potential of this protocol in organic synthesis.