A New Reaction Sequence Involving Palladium-Catalyzed Unsymmetrical Aryl Coupling

Biphenylylalkenes containing an ortho substituent in one ring and a different ortho-, meta-, or para-substituent in the other are prepared in satisfactory yield from an ortho-substituted aryl iodide, an ortho-, meta-, or para-substituted aryl bromide, a terminal olefin, and a base in DMF under the joint catalytic action of palladium(0) and norbornene.