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4-Methoxyphenyl 3-O-benzyl-2-O-levulinoyl-α-D-fucopyranoside (6) (971 mg, 2.12 mmol) was azeotroped 2 times with toluene and dissolved in 20 mL of dichloromethane. Pyridine (1.84 g, 1.87 mL, 23.3 mmol) was added and the mixture cooled to 0° C. Triflic anhydride (1.19 g, 0.71 mL, 4.24 mmol) was added and the mixture stirred for 90 min at 0° C. The mixture was quenched by addition of diluted NaHCO3 solution, the phases were separated and the organic layer extracted 3 times with 3% hydrochloric acid, once with water, dried over Na2SO4 and was concentrated. The resulting crude product was azeotroped 3 times with toluene to remove all traces of pyridine and dried for 1 h in vacuo. The yellow product was dissolved in 25 mL of DMF and sodium azide (3.58 g, 55.1 mmol) was added, and the reaction mixture stirred overnight. The mixture was diluted with water and EtOAc, the phases were separated. The organic phase was washed 3 times with brine, dried over Na2SO4 and concentrated. Column chromatography (3:1 hexane/EtOAc) afforded 816 mg (80%, 2 steps) of 7 as a slightly yellow oil: [α]D: +192.6 (c=1.25, CHCl3). IR (thin film, CHCl3): 3015, 2103, 1739, 1713, 1503, 1400, 1359, 1159, 1034 cm−1. 1H NMR (CDCl3, 300 MHz) δ 1.31 (d, J=6.3 Hz, 3H), 2.14 (s, 3H), 2.58 (m, 2H), 2.69 (m, 2H), 3.26 (t, J=9.9 Hz, 1H), 3.77 (s, 3H), 3.83 (m, 1H), 4.08 (m, 1H), 4.84 (d, J=10.8 Hz, 1H), 4.90 (d, J=10.8 Hz, 1H), 4.96 (dd, J=9.9 Hz, J=3.6 Hz, 1H), 5.48 (d, J=3.3 Hz, 1H), 6.83 (d, J=9.0 Hz, 2H), 6.99 (d, J=9.0 Hz, 2H), 7.31-7.42 (m, 5H). 13C NMR (CDCl3, 75 MHz). 18.4, 28.0, 29.8, 37.8, 55.7, 66.8, 67.9, 73.6, 75.4, 76.6, 78.1, 95.7, 114.6, 118.2, 127.8, 127.8, 128.3, 137.8, 150.4, 155.2, 171.9, 205.7. MALDI-HRMS: m/z [M+Na]+ calcd 506.1898, obsd 506.1889.

1. customThe mixture was quenched by addition of diluted NaHCO3 solution
2. customthe phases were separated
3. extractionthe organic layer extracted 3 times with 3% hydrochloric acid
4. dry with materialonce with water, dried over Na2SO4
5. concentrationwas concentrated
6. customThe resulting crude product was azeotroped 3 times with toluene
7. customto remove all traces of pyridine
8. customdried for 1 h in vacuo
9. dissolutionThe yellow product was dissolved in 25 mL of DMF
10. stirringthe reaction mixture stirred overnight
11. customthe phases were separated
12. washThe organic phase was washed 3 times with brine
13. dry with materialdried over Na2SO4
14. concentrationconcentrated
15. customColumn chromatography (3:1 hexane/EtOAc) afforded 816 mg (80%, 2 steps) of 7 as a slightly yellow oil