Electrochemically Driven Tandem Addition–Cyclization: Synthesis of Thiadiazinanes and Thiophosphonates

Abstract

We herein report a robust electrochemical one-pot two-step strategy for the efficient synthesis of valuable 1,2,5-thiadiazinane and thiophosphonate derivatives. The methodology employs electricity as a clean oxidant and catalytic tetrabutylammonium iodide (TBAI) as both ionic conductor and redox mediator, enabling effective S–N and S–P bond formation under mild conditions. This protocol exhibits broad functional group compatibility, excellent scalability, and generates only hydrogen gas as a by-product, underscoring its environmental benignity. Additionally, it allows late-stage functionalization of natural products and drug derivatives, underscoring its synthetic versatility. Notably, this represents the first electrosynthetic route to 1,2,5-thiadiazinanes, providing a concise, sustainable, and scalable approach to this underexplored yet biologically significant class of heterocycles.