Nonafluorobutanesulfonyl Azide: A Shelf‐Stable Diazo Transfer Reagent for the Synthesis of Azides from Primary Amines

Abstract Nonafluorobutanesulfonyl azide is an efficient, shelf‐stable and cost‐effective diazo transfer reagent for the synthesis of azides from primary amines. The reagent can also be successfully applied to the one‐pot regioselective synthesis of 1,2,3‐triazoles from primary amines by a sequential diazo transfer and azide–alkyne 1,3‐dipolar cycloaddition process catalyzed by copper. The cycloaddition step can be conducted in an inter‐ or intramolecular way to afford 1,4‐ or 1,5‐disubstituted triazoles, respectively. The atypical 1,5‐regioselectivity under copper catalysis is a consequence of geometrical constraints of the amino‐alkyne substrates used in the intramolecular version. Nonafluorobutanesulfonyl azide offers an advantageous alternative to the better known and most commonly used trifluoromethanesulfonyl azide.