Photoinduced C(sp²)–H/C(sp²)–H Cross-Coupling of Alkenes: Direct Synthesis of 1,3-Dienes

A highly concise route to substituted 1,3-dienes from vinylarenes and ketene dithioacetals under photoinduced cross-coupling reaction is described. The reaction proceeded in a highly regio- and stereoselective manner and showed broad functional group tolerance. More than 35 substituted 1,3-dienes were synthesized with good to excellent yields through the construction of the Csp²–Csp² bond without using noble metal and external oxidants, and natural sunlight could also induce the reaction to afford gram-scale synthesis under ambient conditions.