Self‐Promoted Glycosylation for the Synthesis of β‐N‐Glycosyl Sulfonyl Amides

Abstract

AbstractN‐Glycosyl N‐sulfonyl amides have been synthesized by a self‐promoted glycosylation, i. e. without any catalysts, promotors or additives. When the reactions were carried out at lower temperatures a mixture of N‐ and O‐glycosides were observed, where the latter rearranged to give the β‐N‐glycosides at elevated temperatures. By this method sulfonylated asparagine derivatives can be selectively β‐glycosylated in high yields by trichloroacetimidate glycosyl donors of different reactivity including protected glucosamine derivatives. The chemoselectivity in the glycosylations as well as the rearrangements from O‐glycosides to β‐N‐glycosides gives information of the glycosylation mechanism. This method gives access to glycosyl sulfonyl amides under mild conditions.