Copper-Catalyzed Oxidative Arylation and Hydroxylation of Indolin-2-ones for Direct Construction of Tetrasubstituted Carbon Centers

This study introduces a novel methodology for the direct construction of tetrasubstituted centers, utilizing secondary C(sp³)-H and C(sp²)-H substrates, specifically indolin-2-ones and indoles, through an innovative oxidative cross-coupling reaction. Facilitated by a straightforward copper salt catalyst, this reaction proceeds efficiently at a mild temperature of 40 °C under operationally streamlined conditions. Emphasizing sustainability, this method is notably enhanced by employing air (molecular oxygen) as an eco-friendly oxidant. In this approach, air (molecular oxygen) not only serves as the terminal oxidant but also as the oxygen donor in the synthesis of oxygen-containing compounds.