Synlett 2017; 28(16): 2131-2134
DOI: 10.1055/s-0036-1588478
letter
© Georg Thieme Verlag Stuttgart · New York

Fluoropyridyl Sugars – Masked Imidate Glycosyl Donors that Display Reactivity, Selectivity, and Stability

Ray Leslie*
Department of Chemistry, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK   Email: raymond.leslie@ntu.ac.uk
,
Kavnen Tseke
Department of Chemistry, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK   Email: raymond.leslie@ntu.ac.uk
,
Agneta Vitkute
Department of Chemistry, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK   Email: raymond.leslie@ntu.ac.uk
,
Sophie L. Benjamin
Department of Chemistry, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK   Email: raymond.leslie@ntu.ac.uk
,
L. Nitin Seetohul
Department of Chemistry, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK   Email: raymond.leslie@ntu.ac.uk
› Author Affiliations
Further Information

Publication History

Received: 01 June 2017

Accepted: 01 June 2017

Publication Date:
11 July 2017 (online)


Abstract

Fluoropyridyl glycosides, synthesized from the corresponding glycosyl bromides, are shown to be excellent donors in glycosylation reactions. Both armed and disarmed donors were prepared and reacted smoothly with a series of glycosyl acceptors. Coupling proceeded in high yields, with activation of the donor achieved using a range of promoters, and also displayed unusually high selectivity. In addition these novel systems offer the potential for introducing a series of glycosyl donors with ‘tunable reactivity’.

Supporting Information

 
  • References and Notes

  • 2 Kolarich ID. Lepenies B. Seeberger PH. Curr. Opin. Chem. Biol. 2012; 16: 214
  • 3 Wolfert MA. Boons G.-J. Nat. Chem. Biol. 2013; 9: 776
  • 4 Kreisman LS.C. Cobb BA. Glycobiology 2012; 22: 1019
  • 5 Paszek MJ. DuFort CC. Rossier O. Bainer R. Mouw JK. Godula K. Hudak JE. Lakins JN. Wijekoon AC. Cassereau L. Rubashkin MG. Magbanua MJ. Thorn KS. Davidson MW. Rugo HS. Park JW. Hammer DA. Giannone G. Bertozzi CR. R. Weaver VM. Nature 2014; 511: 319
    • 6a Fang T. Mo K.-F. Boons G.-J. J. Am. Chem. Soc. 2012; 134: 7545
    • 6b Guazzelli L. Ulc R. Oscarson S. Carbohydr. Res. 2014; 389: 57
    • 6c Ranade SC. Demchenko AV. Carbohydr. Res. 2015; 403: 115
    • 6d Mootoo DR. Konradsson P. Udodong U. Fraser-Reid B. J. Am. Chem. Soc. 1988; 110: 5583
    • 6e Zhu XM. Schmidt RR. Angew. Chem. Int. Ed. 2009; 48: 1900
  • 7 Agoston K. Streicher H. Fugedi P. Tetrahedron: Asymmetry 2016; 27: 707
    • 8a Nicolaev AV. Kochetkov NK. Isv. Akad. Nauk SSR. Ser. Khim. 1986; 2556
    • 8b Hanessian S. Saavedra OM. Mascitti V. Marterer W. Oehrlein R. Mak C.-P. Tetrahedron 2001; 57: 3267
    • 8c Yu B. Tao H. Tetrahedron Lett. 2001; 52: 2405
  • 9 Huchel U. Schmidt C. Schmidt RR. Eur. J. Org. Chem. 1998; 1353
  • 10 General Procedure for Fluoropyridyl Glycosides: Synthesis of Donor 2 Silver(I) 3-trifluoromethyl-2-pyridoxide (3.91 g, 14.48 mmol) was added to a vigorously stirring solution of acetobromogalactose (4.95 g, 12.05 mmol) in toluene (100 mL) and the mixture heated at reflux for 1 h. The mixture was cooled, filtered through Celite®, and the Celite® pad washed with toluene (100 mL). The combined organic extract was washed with water (100 mL), sat. aq NaHCO3 (100 mL), and dried (MgSO4). Filtration and evaporation of the solvent and purification of the residue by flash chromatography (50% EtOAc/PE) gave the title compound 2 as a white solid (4.93 g, 83%). IR (neat): νmax= 2976, 1758, 1450, 1371, 1213, 1031 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.33 (d, 1 H, PyCH-6, J PyCH-5, 6 = 5.0 Hz), 7.91 (d, 1 H, PyCH-4, J PyCH-4, 5 = 7.8 Hz), 7.1 (dd, 1 H, PyCH-5, J PyCH-5, 6 = 7.8 Hz and J PyCH-4, 5 = 5.0 Hz), 6.03 (d, 1 H, H-1, J 1, 2 = 8.2 Hz), 5.57 (d, 1 H, H-2, J 2  3 = 10.4 Hz), 5.47 (d, 1 H, H-4, J 3, 4 = 3.3 Hz), 5.14 (dd, 1 H, H-3, J2, 3 = 10.4 Hz and J 3, 4 = 3.3 Hz), 4.17 (s, 3 H, H-5, H-6a and H-6b), 2.19 (s, 3 H, CH3) 2.02 (s, 3 H, CH3) 2.00 (s, 3 H, CH3) 1.97 (s, 3 H, CH3) ppm. 13C NMR (100 MHz, CDCl3: δ = 170.45 (2 C), 170.28 and 169.09 (C=O) 158.40 (1 C, PyC-2) 150.48 (1 C, PyC-6) 137.05, 137.01 (1 C, q, PyC-4, J = 4.79 Hz) 123.81 and 121.10 (1 C, q, CF3, J C,F =272.2 Hz) 118.31 (1 C, PyC-5) 114.46, 114.11, 113.78 and 113.44 (1 C, q, PyC-3, J C,F3 = 33.5 Hz), 94.62 (C-1) 71.43, 71.05, 67.85 and 66.97 (C-2 to C-5) 61.12 (C-6) 20.81, 20.77, 20.71 and 20.53 (CH3) ppm. ESI-MS: m/z = 493 (1) [M+], 331 (45) [M+ – C5H3NCF3], 169 (80), 43 (100). HRMS: m/z calcd for C20H22NO10F3Na: 516.1094; found: 516.1172.
  • 11 General Procedure for Glycosylation: Synthesis of Disaccharide 4 Galactoside donor 1 (1.23 g, 2.79 mmol), acceptor 3 (0.83 g, 2.33 mmol), and powdered 4 Å MS (2.00 g) were added to CH2Cl2 (50 mL) and the mixture stirred for 30 min. Copper(II) triflate (1.01 g, 2.79 mmol) was added to the mixture in one portion and stirring continued for a further 60 min. The reaction mixture was filtered, the filtrate washed with CH2Cl2 (25 mL), and the combined organic extracts washed with water (2 × 25 mL), sat. aq NaHCO3 (25 mL), and dried (MgSO4). Filtration and evaporation of the solvent and purification of the residue by flash chromatography (25% EtOAc/PE) gave the title compound 4, as the β anomer, as a white solid (0.64 g, 45%). IR (neat): νmax= 2988, 1743, 1369, 1212, 1062 cm–1. 1H NMR (400 MHz, CDCl3): δ = 5.49 (d, 1 H, H-1′, J 1,2′ = 5.03 Hz), 5.37 (d, 1 H, H-4, J 3,4 = 3.2 Hz), 5.2 (dd, 1 H, H-2, J 2,3 = 10.52 Hz, J 1,2 = 8.23 Hz), 5.0 (dd, 1 H, H-3, J 2,3 = 10.52 Hz, J 3,4 = 3.2 Hz), 4.56–4.58 (m, 2 H, H-1 and H-3′), 4.28 (dd, 1 H, H-2′, J 1,2′ = 5.03 Hz, J2,3′ = 2.29 Hz), 4.01–4.18 (m, 4 H, H-6a, H-6b, H-5, and H-4′), 3.87–3.93 (m, 2 H, H-6a′ and H-6b′), 3.66 (m, 1 H, H-5′), 2.12 (s, 3 H, CH3), 2.07 (s, 3 H, CH3), 2.03 (s, 3 H, CH3), 1.97 (s, 3 H, CH3), 1.49 (s, 3 H, CH3′), 1.43 (s, 3 H, CH3′), 1.31 (s, 6 H, CH3′) ppm. 13C NMR (100 MHz, CDCl3): δ = 170.51, 170.37, 170.28 and 169.79 (C=O), 109.50 and 108.77 (Cquart′), 102.90 (C-1), 96.28 (C-1′), 71.37 (C-2′), 70.90 (C-4′), 70.72 (C-3′), 70.64 (C-3), 70.51 (C-2), 69.74 (C-5), 68.68 (C-5′), 67.96 (C-4), 67.14 (C-6′), 61.28 (C-6), 26.14, 26.02, 25.15 and 24.38 (CH3′), 20.90, 20.79 and 20.71 (CH3) ppm.
  • 12 Ryan DA. Gin DY. In Glycoside Synthesis from 1-Oxygen Substituted Glycosyl Donors . Demchenko AV. Wiley-VCH; Weinheim: 2008: 95
  • 13 Murakami T. Sato Y. Furusawa K. Carbohydr. Res. 2007; 342: 1009
  • 14 Grayson EJ. Ward SJ. Hall AL. Rendle PM. Gamblin DP. Batsanov AS. Davis BG. J. Org. Chem. 2005; 70: 9740
    • 15a Fraser-Reid B. Udodong UE. Wu Z. Ottosson H. Merritt JR. Rao CS. Roberts C. Madsen R. Synlett 1992; 927
    • 15b Boons G.-J. Grice P. Leslie R. Ley SV. Yeung LL. Tetrahedron Lett. 1993; 34: 8523
    • 16a Nashed EM. Glaudemans CP. J. J. Org. Chem. 1987; 52: 5255
    • 16b Graziani A. Passacantilli P. Piancatelli G. Tani S. Tetrahedron Lett. 2001; 42: 3857
  • 17 St-Pierre G. Hanessian S. Org. Lett. 2016; 18: 3106