DIDMH in combination with triflic acid - A new promoter system for thioglycoside glycosyl donors.

We have explored the possibility of using 1,3-diiodo-5,5-dimethylhydantoin (DIDMH) as an alternative to N-iodosuccinimide (NIS) for activation of glycosyl donors of the thioglycoside type in various glycosylation reactions. DIDMH was found to match NIS when it comes to the capability to activate thioglycosides and provide glycosylation products in good yields. Notably, with the two equivalents of reactive iodonium ions per molecule of DIDMH less mass needs to be added making this activator a more atom economically alternative to NIS. Furthermore, DIDMH was found to be stable upon storage for weeks and comparably priced to NIS. With this knowledge in hand we therefore encourage the carbohydrate community to consider using DIDMH for activation of thioglycosides in glycosylation reactions.