Cross-dehydrogenative coupling of secondary benzylic ethers with indoles and pyrroles.

Graphical abstract Highlights • The first cross-dehydrogenative coupling of secondary benzylic ethers. • Isochroman-based tertiary ether synthesis in high efficiency. • Coupling of α-substituted isochromans with indoles and pyrroles. • The first example of catalytic asymmetric cross-dehydrogenative coupling leading to quaternary center. Abstract Current studies on cross-dehydrogenative coupling of benzylic ethers for new C–C bond construction predominantly focus on primary ether moieties. Oxidative cross-coupling of secondary benzylic ethers remains elusive. Herein, we describe the first cross-dehydrogenative coupling of secondary benzylic ethers with indoles and pyrroles for tertiary ether construction. A broad range of α-aryl substituted isochromans react with a variety of electronically varied indoles and pyrroles smoothly under mild metal-free conditions in high efficiency. In addition, the catalytic asymmetric variant was preliminarily explored, and corresponding tertiary ether was obtained in 69% ee. [ABSTRACT FROM AUTHOR]