Highly Chemoselective Palladium-Catalyzed Cross-Trimerization between Alkyne and Alkenes Leading to 1,3,5-Trienes or 1,2,4,5-Tetrasubstituted Benzenes with Dioxygen

A palladium-catalyzed 1:2 linear/cyclic cross-trimerization of alkyne with alkenes using molecular oxygen as the sole oxidant has been reported for the first time. A series of 1,3,5-trienes and 1,2,4,5-tetrasubstituted benzenes are obtained with high chemoselectivity respectively and mechanisms of these reactions are proposed based on some controlled examination.