It was found that crude 1-glycosylamines, prepared with saturated aqueous NH4HCO3
from reducing sugars, can be coupled with Fmoc-Asp(OPfp)-O(t)Bu in N,N-dimethylformamide-water
mixtures. Purification and removal of the (t)Bu group results in N-beta-glycosides
of Fmoc-Asn-OH which can be used for the solid phase synthesis of glycopeptides.