Electrooxidative C-N coupling of seven-membered cyclic sulfonylimines with piperazines

Sulfonamides are among the most important structural motifs in pharmaceuticals, underscoring the value of developing diverse sulfonamide derivatives. We herein report an efficient and environmentally benign method for the electrochemical oxidative C-H/N-H cross-coupling between seven-membered cyclic sulfonylimines and piperazines. The reaction proceeds under transition-metal-, oxidant-, and base-free conditions. Using KI as an electrocatalyst, this method provides access to functionalized medium-sized cyclic sulfonylimines in moderate to excellent yields (up to 96%) with broad functional group tolerance. Notably, preliminary in vitro biological evaluation revealed that compounds 3t, 3x, and 3z demonstrated promising anti-inflammatory activity.