α-Functionalization of Ethers with Acridanes and Amines via Metal-Free Direct C(sp3)-H Radical-Radical Cross-Dehydrogenative Coupling

Abstract

A metal-free, direct radical-radical cross-dehydrogenative coupling (CDC) of relatively unactivated C(sp3)—H bond of ethers with the C(sp3)—H bond of acridanes and amines has been developed, enabling the construction of C9-etherified acridanes and α-etherified amines in moderate to excellent yields using tert-butyl hydroperoxide (TBHP) as the sole oxidant. Mechanistic investigations, including characterization of TEMPO-adduct by single crystal X-ray analysis and isotope labeling experiments, further substantiate the radical-radical coupling pathway.