1: octyl 2,3,4-tri-O-acetyl-6-O-trityl-β-D-glucopyranoside With hydrogen; palladium on activated charcoal in methanol T=20°C; 2: 2,3,4-tri-O-acetyl-α-D-arabinopyranosyl bromide With silver trifluoromethanesulfonate; N,N,N',N'-tetramethyl-urea in dichloromethane T=20°C; 0.5 h;