C3-Heteroarylation of Indoles via Cu(II)-Catalyzed Aminocupration and Subsequent Nucleophilic Addition of o-Alkynylanilines

Transition-metal-catalyzed aminometalation of o-alkynylanilines is a promising pathway for the synthesis of C3-functionalized indoles. Herein, we describe the Cu(II)-catalyzed site-selective C3-heteroarylation of indoles from o-alkynylanilines and quinoline N-oxides. A plausible reaction mechanism involving the aminocupration of o-alkynylanilines followed by the nucleophilic addition of Cu(II)-indolyl complexes to quinoline N-oxides was proposed. Post-transformations of the generated C3-heteroarylated indoles demonstrated the broad applicability of the developed method.