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 pallada-cycles able to promote arylation of their aromatic part. Norbornene deinsertion
Sequential Unsymmetrical Aryl Coupling of <i>o</i>-Substituted Aryl Iodides with <i>o</i>-Bromophenols and Reaction with Olefins: Palladium-Catalyzed Synthesis of 6<i>H</i>-Dibenzopyran Derivatives
Dibenzopyran derivatives are prepared by palladium- and norbornene-catalyzed reaction of aryliodides, o-substituted with electron-releasing substituents, o-bromophenols, and activated alkenes.