Cu-Catalyzed Oxidative C(sp 2 )-H Cycloetherification of o -Alkenyl Arenols for the Preparation of Fused Furans.

A practically efficient, copper-catalyzed approach for the synthesis of functionally embellished indeno-naphthofurans is developed from 1-(1 H -inden-3-yl)naphthalen-2-ols. This intramolecular cycloetherification proceeds via C(sp 2 )-H oxygenation (C-H bond breaking and C-O bond forming), which enables the atom-economical synthesis of poly fused furans in high yields with large substrate diversity in the open air.