Copper-Catalyzed Sulfonyl Azide–Alkyne Cycloaddition
Reactions: Simultaneous Generation and Trapping of Copper–Triazoles
and −Ketenimines for the Synthesis of Triazolopyrimidines
First
simultaneous generation and utilization of both copper–triazole
and −ketenimine intermediates in copper-catalyzed sulfonyl
azide–alkyne cycloaddition reactions is achieved for the one-pot
synthesis of triazolopyrimidines via a novel copper-catalyzed multicomponent
cascade of sulfonyl azides, alkynes, and azirines. Significantly,
the reaction proceeds under very mild conditions in good yields