(Methyl)thianthrenium Salt Assisted Metal-Free Protocol for the Synthesis of N- Sulfonyl Formamidines

Abstract A new strategy for the rapid and efficient synthesis of N-sulfonyl formamidines has been developed through the activation of N,N-dimethylformamide (DMF), assisted by (Methyl)thianthrenium salt under ambient conditions. The protocol offers a metal and oxidant-free process, utilizing a bench-stable and recyclable thianthrenium salt as an activator, via a convenient procedure. The protocol exhibits broad substrate compatibility and scalability. The practical utility of the method has been further demonstrated through the late-stage functionalization of pharmaceutically relevant drug molecules.