Photoinduced, Copper-Catalyzed Three-Component Annulation of gem-Dialkylthio Enynes.

Photoinduced, copper-catalyzed three-component radical annulation of gem-dialkylthio enynes, cyclobutanone oxime esters, and boronic acids was achieved, forming highly functionalized aryl thienyl sulfides with both good chemo- and diastereoselectivities. The reaction proceeds through a domino sequence involving cyanoalkyl radical-mediated intramolecular annulation of gem-dialkylthio enyne, alkenyl radical-promoted C(sp3)-S bond cleavage, and sulfur-centered radical-trapped Cu(II)-facilitated C-S cross-coupling. The protocol features simultaneous establishment of cyanoalkyl, cyclopentanone, and thiophene moieties and a thioether C-S bond in one pot with broad substrate scopes and versatile functional group tolerance under mild conditions.