Efficient Electrosynthesis of Thiazolidin-2-imines via Oxysulfurization of Thiourea-Tethered Terminal Alkenes Using the Flow Microreactor

Sulfur-containing scaffolds play a significant role in many important biological processes. The thiazole-2-imine derivatives have gained significant biological attention due to their interesting pharmacological activities and act as potential therapeutic agents. Many of their syntheses suffer from the drawbacks such as the handling of toxic reagents, harsh reaction conditions, longer reaction times and tedious separation procedures. To their easy access, we applied first time flow electrochemical approach under free supporting electrolytes conditions and without the use of expensive catalysts and reagents. This is not only the first electrochemical cyclization to access thiazolidin-2-imines also represents the first intramolecular sulfurization of unfunctionalized terminal alkenes. This flow electrolysis of N-allylic thioureas generates radical intermediates of nitrogen and sulfur that cyclized via oxysulfurization of terminal alkenes and gives thiazolidin-2-imines with good to high yields under mild, green and environmentally friendly conditions.