Trichloroacetonitrile → O-(2,3,4-tri-O-acetyl-beta-L-fucopyranosyl) trichloroacetimidate

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Reaction Steps

A mixture of 2,3,4-tri-O-acetyl-L-fucopyranose (anomer mixture) (0.50 g, 1.72 mmol), lithium chloride (73 mg, 1.72 mmol), 1,8-diazabicyclo-[5.4.0]-undec-7-ene (0.20 ml, 1.34 mmol) and trichloroacetonitrile (2.0 ml, 20 mmol) in 20 ml of dry acetonitrile is stirred under nitrogen and at room temperature for about 12 h. After chromatographic purification (petroleum ether/diethyl ether 2:5), a mixture of O-(2,3,4-tri-O-acetyl-α-L-fucopyranosyl) trichloroacetimidate (3) and O-(2,3,4-tri-O-acetyl-β-L-fucopyranosyl) trichloroacetimidate (2) is obtained in a yield of 92% (α:β=6.5:1).

Provenance & Evidence