Photochemical Dual‐Catalytic Synthesis of Alkynyl Sulfides

A photochemical dual‐catalytic cross‐coupling to form alkynyl sulfides via C(sp)−S bond formation is described. The cross‐coupling of thiols and bromoalkynes is promoted by a soluble organic carbazole‐based photocatalyst using continuous flow techniques. Synthesis of alkynyl sulfides bearing a wide range of electronically and sterically diverse aromatic alkynes and thiols can be achieved in good to excellent yields (50–96 %). The simple continuous flow setup also allows for short reaction times (30 min) and high reproducibility on gram scale. In addition, we report the first application of photoredox/nickel dual catalysis towards macrocyclization, as well as the first example of the incorporation of an alkynyl sulfide functional group into a macrocyclic scaffold.