Photoinduced stereoselective hydroalkylation of terminal arylalkynes via C(sp3)-H functionalization

A photoinduced stereoselective hydroalkylation of terminal arylalkynes via C(sp3)-H activation was developed. This method employed an organic dye 2,4,5,6-tetrakis(carbazol-9-yl)-1,3‑dicyanobenzene (4CzIPN) as photosensitizer and N-hydroxyphthalimide (NHPI) as the HAT catalyst, which totally inhibited the usage of transition metals and stoichimetrical oxidant or radical initiators (e.g. TBHP). The method also displayed good functional tolerance, allowing access to 1,2-disubstituted alkenes in (Z)-major stereo-selectivity. Primary mechanism studies suggested that the reaction proceed via an electron-catalyzed process.