Activation of glycosyl methylpropiolates by TfOH was investigated. Armed and superarmed glycosyl donors can be activated by use of 0.2 equivalent TfOH whereas 1.0 equivalent of TfOH was required for the activation of the disarmed glycosyl donors. All the glycosidations gave very good yields. The method is suitable for synthesis of glycosides and disaccharides and it may result in the hydrolysis of the interglycosidic bond if the sugar at the non-reducing end is armed or superarmed. These problems are not seen when gold-catalyzed activation procedures are invoked for the activation of glycosyl alkynoates. Display omitted •Methylpropiolate glycosides are explored as glycosyl donors.•Sub-stoichiometric quantity (0.2 equivalents) of Brønsted acid (TfOH) was sufficient to activate armed and super armed glycosyl donors.•TfOH (1.0 equivalents) is required for disarmed glycosyl donors.•The glycosyl donor chemistry is suitable for the synthesis of glycosides and disaccharides.•Attempts to synthesize higher oligosaccharides led to the hydrolysis of the interglycosidic bond.