Oxygen-Promoted Palladium(II) Catalysis: Facile C(sp2)−C(sp2) Bond Formation via Cross-Coupling of Alkenylboronic Compounds and Olefins

[reaction: see text] Oxygen-promoted Pd(II) catalysis facilitated the synthesis of conjugated dienes by cross-coupling of alkenylboronic compounds and various olefins including highly substituted alkenes and cyclohexenone. Under mild conditions, these versatile reactions were efficient and highly stereoselective.