Electrochemical Cyclization–Desulfurization Approach for the Synthesis of 1,3-Benzoxazines Using Cascade C–O and C–N Bond Formation

A cost-effective, eco-friendly, and highly efficient
one-pot electrochemical
process has been described for the synthesis of 4H-1,3-benzoxazine and 4,5-dihydro-1,3-benzoxazepine derivatives by
employing 2-aminobenzyl alcohols, 2-(2-aminophenyl)ethan-1-ol, isothiocyanate
derivatives, and TBAPF6 as an electrolyte. The developed
method is accomplished at 25 °C with a constant current of 20
mA. Utilizing a graphite anode and a platinum cathode in a dimethyl
sulfoxide solvent, the devised metal-free electrochemical approach
minimizes the production of waste and eliminates the need for external
oxidizing agents. Furthermore, the synthesis of these valuable molecules
by employing an electrochemical approach significantly enhances the
ongoing trends in synthetic organic chemistry.