Electrochemical\nReductive Bimolecular Cycloaddition\nof 2‑Arylideneindane-1,3-diones for the Synthesis of Spirocyclopentanole\nIndane-1,3-diones

An electrochemical reductive bimolecular cycloaddition\nof 2-arylideneindane-1,3-diones\nhas been reported for the synthesis of spirocyclopentanole indane-1,3-diones\nbearing five contiguous stereocenters with vicinal tetrasubstituted\nstereocenters, especially involving a quaternary carbon center, in\nmoderate to good yields and excellent diastereoselectivities. The\npresent protocol features mild reaction conditions, no external chemical\nredox reagents, excellent atom economy, and gram-scale synthesis.\nIn addition, a mechanistic investigation indicates that the reactions\nproceed through a radical pathway.