Regioirregular and catalytic Mizoroki–Heck reactions

The palladium-catalysed cross-coupling reaction between alkenes and aryl halides (the Mizoroki–Heck reaction) is a powerful methodology to construct new carbon–carbon bonds. However, the success of this in part hampered by an extremely marked regioselectivity on double bond, which dictates that electron-poor react exclusively β-carbon. Here, we show ligand-free, few-atom palladium clusters solution catalyse α-selective intramolecular coupling iodoaryl cinnamates, mechanistic studies support formation sterically encumbered cinnamate–palladium cluster intermediate. Following rationale, intermolecular iodides with styrenes also achieved encapsulated within fine-tuned restricted zeolite cavities produce 1,1-bisarylethylenes, are further engaged metal-free photoredox-catalysed coupling. These ligand-free methodologies significantly expand chemical space standard usually makes Now, versions electron-deficient reported, giving access otherwise difficult-to-synthesize products.