Direct Condensation of Sulfonamide and Formamide: NaI-Catalyzed Synthesis of <i>N</i>-Sulfonyl Formamidine Using TBHP as Oxidant
作者:Shulin Chen、Yuan Xu、Xiaobing Wan
DOI:10.1021/ol2024604
日期:2011.12.2
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.
Otherwise inert reaction of sulfonamides/carboxamides with formamides via proton transfer-enhanced reactivity
NBS-mediated addition–elimination reaction of sulfonamides/carboxamides and formamides afforded N-sulfonylamidines and N-formylarylamides, respectively, depending on the different mechanism of elimination. Hydrogen bond-induced proton transfer leads to enhanced reactivities and was proposed as the key driving force for the reaction to take place. The protocol demonstrates the possibility of constructing chemical bonds based on a proton transfer strategy induced by noncovalent hydrogen bond interaction.