Iodine-mediated electrocatalysis assist Annulation/cyclization via Intramolecular Benzylic C–H Amination: Batch vs Flow Electrochemistry

Abstract

The access of heterocyclic compounds via direct amination of C-H bonds are of vital interest because of their role in pharmaceutical and natural products. The combination of molecular iodine and electricity activates benzylic C-H bond and facilitates the amination process via intramolecular C-N bond formation. Iodine works as a mediator for the formation of C-N bond via activation of a distance C-H bond through intermediate N-I bond under electrochemical conditions, so iodine can be called electrocatalyst. Under both batch & flow electrochemistry conditions, similar results were obtained in cyclization product with 77 & 78% yields respectively. However, in case of annulation reaction higher yield was obtained with 99% conversion under flow electrochemical conditions using our design of home-made flow microreactor. In both electrochemical transformations, cyclization as well as annulation reaction, no photocatalyst was used. Notably, flow reactions work under safe & environmentally friendly conditions, and continuous products are obtained.