Electrochemical Strain-Release Cascade Cyclization of N‑Aryl Bicyclobutyl Amides with 1,3-Dicarbonyl Compounds via Direct C(sp3)–H/C(sp2)–H Functionalization

Abstract

We report an electrochemical strain-release driven cascade cyclization of N‑aryl bicyclobutyl amides with 1,3-dicarbonyl compounds under mild conditions. This operationally simple electro-oxidative procedure enables sequential C(sp³)-H and C(sp²)-H functionalization, offering an efficient route to access functionalized spirocyclobutyl oxindoles in moderate to excellent yields, without the need for super-stoichiometric oxidants or noble-metal catalysts. In addition, the reaction demonstrates broad applicability across a wide range of symmetrical and asymmetrical 1,3-dicarbonyl compounds, including diesters, ketoesters and diketones.