Chelation-assisted α and β C-H functionalization of aryl alkenes with alkynes and alkenes

The alpha C-H alkenylation of trans- and cis aryl alkenes through hydroalkenylation of alkynes was demonstrated to be proceeded by the formation of a six-membered exo-palladacycle, affording a wide range of conjugated dienes with an excellent E/Z ratio selectivity. Moreover, the oxidative beta C-H alkenylation of dienes using alkenes was investigated to produce conjugated trienes through a seven-membered endo-palladacycle. The chemical derivation and photophysical properties of polyene products were also investigated. alpha C-H alkenylation of aryl alkenes by six-membered exo-palladacycles was demonstrated to afford aryl dienes, which underwent beta C-H alkenylation through seven-membered endo-palladacycles to produce aryl trienes with excellent E/Z ratio selectivity.