A Cu(I)-catalyzed interrupted click reaction, using N-chlorophthalimide as electrophilic chlorine source, enabling the facile synthesis of 1,4,5-trisubstituted 5-chloro-1,2,3-triazoles in one step from readily available terminal alkynes and azides is reported. This approach allowed complete control of regioselectivities with a broad substrate scope. Furthermore, a novel epoxidation was developed using 5-chloro-triazole as substrate, which could be further applied in various organic transformations.

Abstract

5-Halo-1,2,3-triazoles are important scaffolds in organic chemistry, but current click reactions cannot produce 1,4,5-trisubstituted 5-chloro-1,2,3-triazoles in a simple way. Herein, we disclosed a Cu(I)-catalyzed interrupted click reaction, using N-chlorophthalimide as an electrophilic chlorine source, enabling the facile synthesis of 1,4,5-trisubstituted 5-chloro-1,2,3-triazoles in one step from readily available terminal alkynes and azides. Complete control of regioselectivities with a broad substrate scope was accomplished by this approach. Furthermore, a novel epoxidation was developed using 5-chloro-triazole as substrate, which could be further applied in various organic transformations.