Using In(III) as a promoter for glycosylation

InCl3, InBr3, and In(OTf)3 were tested as promoters in the preparation of glycosides from trichloroacetimidate precursors. A range of protecting groups and of alcohol acceptors were used to determine the versatility of these promoters. Disaccharide formation was demonstrated. In most cases, the In(III) compounds were shown to promote glycosylation better than the widely used promoter BF3·OEt2.

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► In(OTf)3, InCl3, and InBr3 are convenient catalytic promoters of glycosylation.
► In(III) was used effectively with trichloroacetimidate donors bearing acetyl, benzyl, and acetonide protecting groups.
► Disaccharide formation using In(III) promoters was demonstrated.