Direct Condensation of Sulfonamide and Formamide: Nal-Catalyzed Synthesis of N-Sulfonyl Formamidine Using TBHP as Oxidant

A new N-sulfonyl formamidine synthesis was developed via Nal-catalyzed direct condensation of sulfonamide and formamide. The green methodology is featured by high atom economy, easily available starting materials, the lack of need for a transition-metal catalyst, no requirement of hazardous reagent, operational simplicity, and good tolerance with diverse functional groups. Mechanistic studies suggest that the protocol proceeds based upon in situ generated TsN center dot Nal.