<i>N</i>-Fluorosulfurylamidines Enable Modular Synthesis of 1,5-Disubstituted Tetrazoles

Here we report the modular synthesis of 1,5-disubstituted tetrazoles using two highly chemoselective reactions, ligations of <i>N</i>-fluorosulfurylamidines with amines and diazotransfer reactions between FSO₂N₃ and <i>N</i>-monosubstituted amidines, respectively. Enabled by sulfur(VI) fluoride exchange (SuFEx) click chemistry, we have successfully synthesized a series of <i>N</i>-fluorosulfurylamidines and identified them as stable and scalable organic synthons. We then discover that <i>N</i>-fluorosulfurylamidines react selectively toward a series of aliphatic amines, resulting in the formation of <i>N</i>-monosubstituted amidines that can react further with FSO₂N₃ to deliver 1,5-disubstituted tetrazoles. Our work provides a new platform for generating a library of 1,5-disubstituted tetrazoles with diverse structures, which is unprecedented.