Rapid Construction of Enantioenriched Benzofurochromanes by SaBOX/Copper(II) Catalyzed Enantioselective [3 + 2] Annulation of γ-Chromenes with Quinones.

A rapid construction of enantioenriched benzofurochromanes was developed by SaBOX/copper(II) catalyzed enantioselective [3 + 2] annulation of γ-chromenes with quinones. This process takes advantage of the simple starting materials and a highly efficient chiral SaBOX/copper(II) catalyst system, leading to a variety of benzofurochromanes in up to 96% yield with up to 97% ee.