“…Condensation of d -glucose derivative 1 with nitroethanol under typical Henry reaction conditions gave a 3:2 mixture of epimers 2 in 75% yield (Scheme ). To protect hydroxy groups at C 5 and C 7 , 2 was then treated with benzyl trichloroacetimidate and triflic acid, giving the epimeric mixture 3 , from which the acetonide protecting group was removed by treatment with a 1:1:1 mixture of trifluoroacetic acid, dioxane, and water.…”