Cp*Co(III)-catalyzed synthesis of isoquinolones via controlled annulation of primary arylamides with internal alkynes.

In this study, we present the first cobalt(III)-catalyzed direct synthesis of isoquinolones from readily available primary arylamides and internal alkynes through a controlled oxidative C-H/N-H annulation reaction. This innovative protocol eliminates the need for expensive transition metal salts and external auxiliaries, producing the desired mono-annulated product exclusively while accommodating a wide range of substrates. Preliminary mechanistic studies highlight the critical role of copper oxide in facilitating the transformation. Additionally, peripheral modifications of the core isoquinolone rings have been performed to synthesize complex heterocyclic systems.