Cp*Co(III)-Catalyzed C-H Alkenylation of Aromatic Ketones with Alkenes

Cost-effective and air-stable high-valent cobalt(III)-catalyzed weakly coordinating, ketone-directed regioselective mono-alkenylation of arenes and heteroarenes with alkenes is demonstrated. Various electron-rich and electron-deficient arenes are tolerated under the reaction conditions, providing E-alkenylated products exclusively. The tert-butyl-acrylates serve as an acrylic acid surrogate to provide cinnamic acid derivatives via direct C-H alkenylation. A two-step synthesis of a gamma-PPAR antagonist, the synthesis of indanone, and the modification of divinylsulfone are reported as applications. The mechanistic details suggest a base-assisted intermolecular electrophilic substitution reaction pathway.