Antimony–lithium exchange reaction: Synthesis of 1,4,5-trisubstituted-1,2,3-triazoles by triazolyllithium with electrophiles

Abstract

Trisubstituted 5-stibano-1H-1,2,3-triazoles 3 was synthesized by the Cu-catalyzed [3 + 2] cycloaddition of ethynylstibane 1 with benzyl azide 2 in the presence of CuBr (5 mol%) under aerobic conditions. 5-Stibanotriazole 3 was treated with an equimolecular amount of phenyllithium (PhLi) in anhydrous THF under argon atmosphere at −78 °C. Subsequent treatment with various electrophiles formed 1,4,5-trisubstituted-1,2,3-triazoles 5 containing a benzyl moiety. This reaction is a novel example of an antimony (Sb) – lithium (Li) exchange reaction for the functionalization of heterocycles.