Synthesis of the trisaccharide core m2 building block 14: a) NaH, 4-methoxybenzyl chloride, DMF, RT 2 h; b) Zn, 1,4-dioxane/AcOH 10:1, RT 24 h; NaHCO3, 1,4-dioxane/H2O 2:1, TrocCl, RT 24 h; c) Pyridine/Ac2O, RT.24 h; d) Wilkinson’s catalyst, Tol/EtOAc/H2O 20:10:1, reflux 24 h; I2, THF/H2O 4:1, RT 2 h; e) trichloroacetonitrile, DBU, dichloromethane, 0°C 3 h; f) Fmoc-Thr acceptor 5, TMSOTf, molecular sieves, Et2O, RT 30 min; g) NaOMe in MeOH, pH 9.5, RT 24 h; NaHCO3, 1,4-dioxane/H2O 1:1, Fmoc-OSu, RT 2 h; h) NIS, TfOH, dichloromethane, −50°C 4 h; i) CAN, MeCN/H2O 9:1, RT 30 min;Pyridine/Ac2O, RT 24 h; j) Zn, AcOH, RT 4 days; Pyridine/Ac2O, RT 24 h; k) TFA/dichloromethane 3:1, RT 24 h.