Easy Access\nto Fused Tricyclic Quinoline Derivatives\nthrough Metal-Free Electrocatalytic [4 + 2] Annulation

An efficient electrocatalytic\ncycloaddition approach for the construction\nof a lactone- or lactam-fused quinoline framework is documented. Diverse\narrays of functionalities are well-compatible under this metal-free,\nmild, and scalable electro-redox protocol. Mechanistic studies indicate\nan iodide-mediated electro-oxidation of secondary amines to their\ncorresponding imines and consequent [4 + 2] cycloaddition, fabricating\nC–C bonds followed by rapid aromatization leading to the six-membered\ncore structure.