Interrupted CuAAC‐Thiolation for the Construction of 1,2,3‐Triazole‐Fused Eight‐Membered Heterocycles from O‐/N‐Propargyl derived Benzyl Thiosulfonates with Organic Azides

A copper(I)‐catalyzed interrupted click‐sulfenylation of O‐/N‐propargyl benzyl thiosulfonates with organic azides has been disclosed. The unified CuAAC‐thiolation provides a wide range of triazole‐fused eight‐membered heterocycles in good to high (51–94%) yields under mild reaction conditions. Moreover, a three‐component reaction is also achieved involving O‐/N‐propargyl benzyl thiosulfonates, benzyl bromide, and sodium azide to deliver fused‐triazoles in 61–74% yields. From a synthetic point of view, the present protocol has been demonstrated at gram‐scale reactions. A plausible mechanism is also proposed based on experimental results and control experiments.