<i>N</i>‐Sulfonyl Imidazoliums as the Versatile Coupling Reagents and Sulfonating Reagents in Synthesis of Amides, Esters, Thioesters, Phosphoramides, Phosphoesters, Glycosides, Sulfonamides, and Sulfonates

Here, we report a novel strategy for the first time: bench-stable N-sulfonyl imidazoliums were used as the robust and versatile coupling reagents and sulfonating reagents. Fast reactions of N-sulfonyl imidazoliums with carboxylic acids or phosphodiesters formed carboxylic acid-sulfonic acid mixed anhydrides and phospho-sulfonic acid mixed anhydrides, respectively, and the subsequent treatments of the highly active intermediates with the corresponding nucleophilic partners in the presence of imidazoles at room temperature provided amides, dipeptides, carboxylic esters, carboxylic thioesters (almost without racemization during the formation of amides, dipeptides, esters, thioesters), phosphamides, and phosphoesters in high to excellent yields. This kind of N-sulfonyl imidazolium as the coupling reagent was successfully applied in solid phase synthesis of a polypeptide containing 32 amino acid residues. This strategy was effectively extended to the construction of glycosides, and high steroselectivity and good yields were provided. In addition, reactions of N-sulfonyl imidazoliums with amines or alcohols afforded the corresponding sulfonamides and sulfonates in excellent yields. This study should provide a highly efficient, economical, and practical strategy for construction of diverse molecules.