Highly Regioselective Palladium-Catalyzed Internal Arylation of Allyltrimethylsilane with Aryl Triflates

Highly regioselective ligand-controlled Heck-arylation reactions of allyltrimethylsilane, delivering branched β-products, were performed in moderate to good yields. The high preference for internal over terminal double-bond arylation suggests a contribution from the β-cation-stabilizing effect of silicon. Microwave-promoted palladium-catalyzed coupling reactions proceeded with the same regioselectivity in six entries out of eight with the reaction times cut sharply down to 5−10 min.