Synthesis of selectively substituted ortho-vinylbiphenyls by palladium-catalysed reaction of ortho-substituted aryl iodides with olefins

In the presence of Pd(OAc)(2) and norbornene as catalysts, ortho-substituted aryl iodides and terminal olefins react to afford selectively substituted ortho-vinylbiphenyl derivatives in good yields. The reaction proceeds through a series of steps including norbornene insertion and C-H activation with formation of palladacycles able to promote arylation of their aromatic part. Norbornene deinsertion then leads to the selective formation of a palladium-bonded biphenylyl group able to react with terminal olefins.