Electricity-Driven Strain-Release Cascade Cyclization of Bicyclo[1.1.0]butane (BCB): Stereoselective Synthesis of Functionalized Spirocyclobutyl Oxindoles.

Spirocyclobutyl oxindoles, characterized by their unique three-dimensional structures, are valuable building blocks for many pharmacophores and drug units. However, stereoselective synthetic strategies for these scaffolds remain underdeveloped, with most existing methods relying on transition metal catalysts and stoichiometric redox reagents. In this work, we introduce an electrochemical strain-release driven cascade spirocyclization of bicyclo[1.