Electrochemical Oxidation Dearomatization of Anisol Derivatives toward Spiropyrrolidines and Spirolactones

Spiro compounds are widely prevalent in biological activities and natural products.However,developing new strategies for their efficient synthesis and derivatization remains a challenge.Outstanding progress has been made in the synthesis of spiro compounds through dearomatization of aromatic compounds,most of them are mediated by the hypervalent iodine reagents.Herein,we report a method of anodic oxidation spiroamination and spirolactonization of anisole derivatives with concomitant cathodic reduction of protons in the absence of hypervalent iodine reagents.A wide variety of spiropyrrolidines and spirolactones with diverse functional groups made useful scaffolds in this transformation,with yields up to 97%.Moreover,hectogram-scale synthesis could supply target product with 83% yield in a flow electrochemical cell using carbon paper as the anode and nickel plate as the cathode,demonstrating the potential application of this method.