Development of a Traceless Directing Group: Cp*-Free Cobalt-Catalyzed C-H Activation/Annulations to Access Isoquinolinones

A new traceless directing group, 2-(hydroxymethyl)pyridine, has been reported for the Cp*-free cobalt-catalyzed C-H activation/annulation reaction to synthesize isoquinolinones. The reaction exhibits good functional group tolerance, affording products in good to excellent isolated yields under mild conditions. Notably, the directing group can be removed directly in situ along the catalytic process.