Ruthenium-Catalyzed Selective Aerobic Oxidative ortho-Alkenylation of Substituted Phenols with Alkenes through C-H Bond Activation

The oxidative coupling of phenyl carbamates and acetates with alkenes in the presence of a catalytic amount of [RuCl2(p-cymene)](2), AgSbF6, and Cu(OAc)(2)center dot H2O under air provided substituted alkene derivatives in a highly regioand stereoselective manner. The catalytic reaction was compatible with various alkenes such as acrylates, vinyl sulfones, acrylonitrile, and substituted styrenes. The present catalytic reaction was also compatible with phenyl carbamates and acetates with various electron-rich, electron-deficient, and halogen substituents on the aromatic ring. Further examination of the catalytic reaction was done with the substituted phenyl acetates. By using LiOH center dot H2O or K2CO3 as a base, the substituted alkene derivatives were converted into the corresponding phenol derivatives. To account for the catalytic reaction, a possible mechanism is proposed that involves a sixmembered ruthenacycle as the key intermediate.