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.