Synthesis of Phenanthrone Derivatives from sec-Alkyl Aryl Ketones and Aryl Halides via a Palladium-Catalyzed Dual C-H Bond Activation and Enolate Cyclization

A palladium-catalyzed chelation-assisted C-H activation of alkyl aryl ketones and their reaction with aryl iodides to afford ortho-arylated products is described. For sec-alkyl aryl ketones, the catalytic reaction proceeds further to give 10,10-dialkylphenanthrone derivatives. A possible reaction mechanism involving directed dual C-H bond activation and enolate cyclization for the formation of 10,10-dialkylphenanthrone derivatives is proposed.