Efficient activation of thioglycosides with N-(p-methylphenylthio)-ε-caprolactam-TMSOTf.

N-(p-Methylphenylthio)-ε-caprolactam (1) in combination with trimethylsilyl trifluoromethanesulfonate (TMSOTf) provides an efficient thiophilic promoter system, capable of activating different thioglycosides. Both 'armed' and 'disarmed' thioglycosyl donors were activated for glycosidic bond formation. Notably, this reagent combination works well in reactivity-based one-pot oligosaccharide assembly strategy.