Oligosaccharide synthesis using two fluorous-tagged glycosyl donors.81 Reagents and conditions (a) DMAP, DCM, reflux, 86%; (b) i. HOAc/H2O(3/1), 50 °C, 62%; ii. CCl3CN, DBU, DCM, 77%; (c) TMSOTf, DCM, −20 → 0 °C, 30 min, then TMSOTf, 0 °C → rt, 2 h, 65%.