Abstract Norbornene and norbornadiene derivatives have been shown to react with aryl and vinyl halides in the presence of a palladium catalyst, formic acid, and tributylamine or piperidine to give hydroarylated and hydrovinylated derivatives in good to high yield. Extension of the reaction to the hindered α, β-unsaturated aldehydic system of myrtenal produced a monocyclic derivative through a palladium-catalyzed ring opening.