Trichloroacetimidates as Glycosyl Donors in Recyclable Ionic Liquids

Abstract

The trichloroacetimidates of different glycopyranoses were glycosylated in ionic liquids with different acceptors, affording the corresponding glycopyranosides in fair to excellent yields and allowing to recycle the solvent without additional Lewis acid.

Key words

carbohydrates - ionic liquids - glycosylations - green chemistry - stereoselectivity

References

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7

In a typical procedure the donor (100 mg, 1 equiv) and isopropanol (20 equiv) were dissolved in the ionic liquid (0.5 mL) and trimethylsilyl triflate (0.01 equiv) was added. The reaction was stirred at r.t. The work-up was performed by extracting the ionic liquid in chloroform or toluene (see entries 1 and 2 of Table [2] ) and the crude mixture was purified by flash chromatography.

16

In a typical procedure the acceptor (60 mg, 1 equiv) and trimethylsilyl triflate (0.01 equiv) were dissolved in the ionic liquid (0.5 mL). The donor (1.5 equiv) was added as a solid and the reaction was stirred at r.t. until completion. After extraction with chloroform the crude was purified by flash chromatography.