Direct N-glycosylation of tosyl and nosyl carbamates with trichloroacetimidate donors

Abstract

Under catalyst and additive-free conditions, a convenient and highly efficient eco-friendly method for the stereoselective synthesis of N-glycofuranosyl and glycofuranosyl sulfonamides has been developed. The two-component reaction of glycofuranosyl trichloroacetimidates with a wide range of tosyl and nosyl carbamate acceptors having varying pK_a-values including non-sugar-, and sugar-derived carbamates as well as amino acid-derived carbamates, proceeded smoothly with good yield and β-stereoselectivity. In addition, the selective deprotection of N-carbamates and N-sulfonyl groups of the N-glycoside functioning as orthogonal protective groups was performed for further functionalization of the N-glycosides.