Efficient Stereoselective Synthesis of γ-N-Glycosyl Asparagines by N-Glycosylation of Primary Amide Groups
摘要:
The efficient and elegant synthesis of N-glycosides by N-glycosylation of asparagine-containing peptides is described. Glycosylation of primary amides with glycosyl N-phenyltrifluoroimidates in the presence of a catalytic amount of TMSOTf in nitromethane smoothly proceeded to provide the corresponding N-glycosyl amino acids in excellent yields. This coupling method was adaptable to the coupling of various glycosyl donors with amino acids and peptides.
Dissection of the effects that govern thioglucoside and thiomannoside reactivity
作者:Mads Heuckendorff、Lulu Teressa Poulsen、Christinne Hedberg、Henrik H. Jensen
DOI:10.1039/c7ob02968c
日期:——
Neighboringgroupeffects were investigated in gluco- and manno-configured thioglycosides under NIS/TfOH activation. Donors possessing a 2-O-benzoyl group that are capable (1,2-trans) and incapable (1,2-cis) of exerting nucleophilic push were compared with donors possessing a participatory neutral 2-O-benzyl group. By using competition experiments between sets of glycosyl donors the direct effect of