Communication
3506; Angew. Chem. 2006, 118, 3583; c) A. M. Ali, S. D. Taylor, Angew.
Chem. Int. Ed. 2009, 48, 2024–2026; Angew. Chem. 2009, 121, 2058; d)
L. J. Ingram, A. Desoky, A. M. Ali, S. D. Taylor, J. Org. Chem. 2009, 74,
6479–6485; e) A. Y. Desoky, S. D. Taylor, J. Org. Chem. 2009, 74, 9406–
9412; f) A. Y. Desoky, J. H. Hendel, L. J. Ingram, S. D. Taylor, Tetrahedron
2011, 67, 1281–1287.
1.1 equiv.) was added. The reaction mixture was warmed to room
temperature and stirred for 24 h. The reaction mixture was filtered
through a Celite pad®, which was further rinsed with CH2Cl2. The
combined filtrates were washed with aqueous HCl (0.5
M in H2O),
followed by water. The organic layer was dried with Na2SO4 and
concentrated under reduced pressure. The residue was dissolved in
CH2Cl2 (2.0 mL) and treated with pinacol (59.2 mg, 0.50 mmol,
2.5 equiv.) at room temperature for 16 h. After the mixture had
been concentrated under reduced pressure, the residue was puri-
fied by silica gel column chromatography (CHCl3/AcOEt, 3:1) to give
[9] For seminal work on the introduction of protected sulfate groups into
carbohydrates, see: a) C. L. Penney, A. Perlin, Carbohydr. Res. 1981, 93,
241–246; b) A. D. Proud, J. C. Prodger, S. L. Flitsch, Tetrahedron Lett. 1997,
38, 7243–7246.
[10] Molecular recognition between carbohydrate and phenylboronic acid
has been widely investigated by us and others.[6,11] In general, phenyl-
boronic acid recognizes the hydroxy groups at the C4 and C6 positions
and/or the cis-1,2-diol in the nonprotected methyl hexopyranoside and
regioselectively forms a cyclic boronate ester.
methyl 2-O-(2,2,2-trichloroethyl)sulfo-α- -fucopyranoside (5) as a
L
colorless white solid (63.7 mg, 0.16 mmol, 82 % yield).
Acknowledgments
This work was partially supported by a Kitasato University Re-
search Grant for Young Researchers. We thank Dr. K. Nagai and
Ms. M. Sato at Kitasato University for instrumental analyses.
Keywords: Sulfation · Boronic acid · Regioselectivity ·
Carbohydrates
[1] a) A. Varki, R. D. Cummings, J. D. Esko, H. H. Freeze, P. Stanley, C. R.
Bertozzi, G. W. Hart, M. E. Etzler, Essentials of Glycobiology, 2nd ed., Cold
Spring Harbor Laboratory Press, Woodbury, NY, 2009; b) T. Toida, A.
Chaidedgumjorn, R. J. Linhardt, Trends Glycosci. Glycotechnol. 2003, 15,
29–46.
[2] For a recent review on the chemical sulfation of small molecules, see:
R. A. Al-Horani, U. R. Desai, Tetrahedron 2010, 66, 2907–2918.
[3] a) B. Guilbert, N. J. Davis, S. L. Flitsch, Tetrahedron Lett. 1994, 35, 6563–
6566; b) B. Guilbert, N. J. Davis, M. Pearce, R. T. Aplin, S. L. Flitsch, Tetrahe-
dron: Asymmetry 1994, 5, 2163–2178; c) A. Lubineauc, R. Lemoine, Tetra-
hedron Lett. 1994, 35, 8795–8796; d) B. Abad-Romero, K. Mereiter, H.
Sixta, A. Hofinger, P. Kosma, Carbohydr. Res. 2009, 344, 21–28.
[4] The sulfation reaction with SO3–Et3N for the formation of the stannylene
acetal of the boronate ester of methyl hexopyranoside was reported: S.
Langston, B. Bernet, A. Vasella, Helv. Chim. Acta 1994, 77, 2341–2353.
[5] Glycosylation reactions on the polystyrylboronic acid solid support were
reported as pioneer works: a) G. Belogi, T. Zhu, G.-J. Boons, Tetrahedron
Lett. 2000, 41, 6965–6968; b) G. Belogi, T. Zhu, G.-J. Boons, Tetrahedron
Lett. 2000, 41, 6969–6972; c) D. Crich, S. Sun, J. Am. Chem. Soc. 2002,
124, 8867–8869.
[11] a) R. J. Ferrier, Methods Carbohydr. Chem. 1972, 6, 419–426; b) R. J. Ferrier,
Adv. Carbohydr. Chem. Biochem. 1978, 35, 31–80; c) P. J. Duggan, E. M.
Tyndall, J. Chem. Soc. Perkin Trans. 1 2002, 1325–1339.
[12] Unexpectedly, the cyclic phenylboronate ester of sulfated pyranosides is
stable under the workup procedure, which involves neutral water and
aqueous acid, or purification by silica gel chromatography. However, a
simple treatment of the cyclic phenylboronate ester of sulfated methyl
α-L-fucopyranoside (2) with pinacol under neutral conditions afforded
the desired 2-O-monosulfated product 5.
[13] P. Wang, P. Haldar, Y. Wang, H. Hu, J. Org. Chem. 2007, 72, 5870–5873.
[14] H. C. Kolb, M. G. Finn, K. B. Sharpless, Angew. Chem. Int. Ed. 2001, 40,
2004–2021; Angew. Chem. 2001, 113, 2056.
[15] For a report on propargyl glycosides as stable glycosyl donors, see: S.
Hotha, S. Kashyap, J. Am. Chem. Soc. 2006, 128, 9620–9621.
[16] Water generated as a byproduct in the formation of the phenylboronate
ester could be sufficiently removed by MS (4 Å) before the sulfation
reaction. Therefore, the degradation of Taylor's reagent 1 by water was
suppressed, and the yield was improved in the one-pot sequential pro-
cedure.
[6] a) E. Kaji, T. Nishino, K. Ishige, Y. Ohya, Y. Shirai, Tetrahedron Lett. 2010,
51, 1570–1573; b) T. Nishino, Y. Ohya, R. Murai, T. Shirahata, D. Yamamoto,
K. Makino, E. Kaji, Heterocycles 2012, 84, 1123–1140; c) E. Kaji, D. Yama-
moto, Y. Shirai, K. Ishige, Y. Arai, T. Shirahata, K. Makino, T. Nishino, Eur.
J. Org. Chem. 2014, 3536–3539.
[7] T. H. Fenger, R. Madsen, Eur. J. Org. Chem. 2013, 5923–5933.
[8] a) Y. Liu, I. F. Lien, S. Ruttgaizer, P. Dove, S. D. Taylor, Org. Lett. 2004, 6,
209–212; b) L. Ingram, S. D. Taylor, Angew. Chem. Int. Ed. 2006, 45, 3503–
Received: December 14, 2015
Published Online: January 26, 2016
Eur. J. Org. Chem. 2016, 902–905
905
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