In conclusion, we have developed an efficient one-pot
procedure for the regioselective protection of D-glucopyranoside
derivatives by tandem catalysis mediated by FeCl3ꢁ6H2O. Our
method provides a very fast access to orthogonally protected
saccharides in one vessel under very mild conditions and has
been applied to the a,a-D-trehalose disaccharide and a-methyl
maltoside. It is interesting to note that all four reactions, which
conventionally require anhydrous conditions or dehydrating
agents to be carried out, are conveniently catalyzed in this
work by the easy-to-handle hydrated iron complex. Extension
of this protocol to other mono-, di- and oligosaccharides of
interest is currently in progress in our laboratory and will be
reported in due course.
(c) D. Sherry and A. Furstner, Acc. Chem. Res., 2008, 41, 1500;
¨
(d) E. B. Bauer, Curr. Org. Chem., 2008, 12, 1341.
6 (a) G. Wei, L. Zhang, C. Cai, S. Cheng and Y. Du, Tetrahedron Lett.,
2008, 49, 5488; (b) S. E. Sen, S. L. Roach, J. K. Boggs, G. J. Ewing
and J. Magrath, J. Org. Chem., 1997, 62, 6684; (c) X. Ding, W. Wang
and F. Kong, Carbohydr. Res., 1997, 303, 445.
7 For cleavage bond reactions, see: (a) M. H. Park, R. Takeda and
K. Nakanishi, Tetrahedron Lett., 1987, 28, 3823; (b) J. I.
´ ´
Padron and J. T. Vazquez, Tetrahedron: Asymmetry, 1995, 6,
857; (c) R. Rodebaugh, J. S. Debenham and B. Fraser-Reid,
Tetrahedron Lett., 1996, 37, 5477.
8 Acetal formation promoted by anhydrous FeCl3: (a) P. P. Singh,
Y. M. Gharia, F. Dasgupta and H. C. Srivastava, Tetrahedron Lett.,
´
1977, 18, 439; (b) W. Danikiewicz, M. Olejnik, J. Wojcik, S. K. Tyrlik
and B. Nalewajko, J. Mol. Catal. A: Chem., 1997, 123, 25.
9 Reductive etherification catalyzed by anhydrous FeCl3:
(a) K. Iwanami, H. Seo, Y. Tobita and T. Oriyama, Synthesis,
2005, 183; (b) K. Iwanami, K. Yano and T. Oriyama, Synthesis,
2005, 2669; (c) K. Iwanami, K. Yano and T. Oriyama, Chem. Lett.,
2007, 36, 38.
We thank the Ministere de la Recherche for a grant to AL
and the CNRS for financial support.
10 Acylation: (a) F. Dasgupta, P. P. Singh and H. C. Srivastava,
Carbohydr. Res., 1980, 80, 346; (b) G. V. M. Sharma,
A. K. Mahalingam, M. Nagarjan, A. Ilangovan and
P. Radhakrishna, Synlett, 1999, 1200. With FeCl3ꢁ6H2O as a
catalyst, see; (c) K. Komura, A. Ozaki, N. Ieda and Y. Sugi,
Synthesis, 2008, 3407.
11 The regioselectivity of the reductive etherification was determined
through chemical correlation after acetylation of the hydroxyl
function and was in agreement with previous work. See ref. 2
and C.-C. Wang, J.-C. Lee, S.-Y. Luo, H.-F. Fan, C.-L. Pai,
W.-C. Y, L.-D. Lu and S.-C. Hung, Angew. Chem., Int. Ed.,
2002, 41, 2360.
Notes and references
z Representative procedure (synthesis of compound 3): To an ice-cold
solution of the per-O-silylated a-methyl glucopyranoside 1 (3 g, 6.2 mmol)
and benzaldehyde (1.89 mL, 18.6 mmol, 3 equiv) in dichloromethane
(11.0 mL), a solution of FeCl3ꢁ6H2O in acetonitrile (84.0 mg, 5 mol%,
in 2.7 mL of CH3CN) and triethylsilane (1.09 mL, 6.8 mmol, 1.1 equiv)
was added dropwise. The reaction was stirred at room temperature
and monitored by TLC. After consumption of the starting material,
tetra-n-butylammonium (10.0 mL of a 1 M solution in THF) was
added. The solution was diluted with ethyl acetate and neutralized
with a saturated aqueous NaHCO3 solution. The aqueous layer was
extracted twice with EtOAc. The combined organic layers were dried
over Na2SO4, filtered and concentrated in vacuo. The crude product
was purified by silica gel chromatography to give the expected
compound 3 (1.78 g, 77% yield).
12 G. Cahiez, V. Habiak, C. Duplais and A. Moyeux, Angew. Chem.,
Int. Ed., 2007, 46, 4364.
13 For a recent work see: K. Daragics and P. Fugedi, Tetrahedron
¨
Lett., 2009, 50, 2914 and references cited therein.
14 This sequential addition of the iron catalyst (5 mol% twice) was
more efficient than adding 10 mol% at the onset of the tandem
process.
1 For some key reviews see: (a) L. F. Tietze, Chem. Rev., 1996, 96,
115; (b) S. E. Denmark and A. Thorarensen, Chem. Rev., 1996, 96,
137; (c) D. E. Fogg and E. N. dos Santos, Coord. Chem. Rev., 2004,
248, 2365; (d) A. Ajamian and J. L. Gleason, Angew. Chem., Int.
Ed., 2004, 43, 3754; (e) J.-C. Wasilke, S. J. Obrey, R. T. Baker and
G. C. Bazan, Chem. Rev., 2005, 105, 1001; (f) D. Enders,
15 (a) J.-C. Arguelles, Arch. Microbiol., 2000, 174, 217;
¨
(b) A. D. Elbein, Y. T. Pan, I. Pastuszak and D. Carroll, Glyco-
biology, 2003, 13, 17; (c) M. Gilleron, S. Stenger, Z. Mazorra,
¨
F. Wittke, S. Mariotti, G. Bohmer, J. Prandi, L. Mori, G. Puzo
C. Grondal and M. R. M. Huttl, Angew. Chem., Int. Ed., 2007,
and G. De Libero, J. Exp. Med., 2004, 199, 649.
16 For recent synthetic studies on substituted trehalose derivatives
see: (a) C. D. Leigh and C. R. Bertozzi, J. Org. Chem., 2008, 73,
1008(b) J. Guiard, A. Collmann, M. Gilleron, L. Mori, G. De
Libero, J. Prandi and G. Puzo, Angew. Chem., Int. Ed., 2008, 47,
9734; (c) M. K. Patel and B. G. Davis, Org. Biomol. Chem., 2010, 8,
4232.
17 Under the same conditions, but with a higher concentration, the
reaction mediated by copper(II) triflate provided only 30% yield of
the same compound 10.
18 Higher loadings of catalyst did not improve the yield, probably due
to the concomitant hydrolysis of the benzylidene acetals. See
ref. 6b.
19 The direct bis reductive opening of the benzylidene acetals in
compound 10 under identical conditions led to a complex mixture
of partially reduced and/or hydrolyzed products, highlighting
again the interest of the tandem procedure.
¨
46, 1570; (g) N. Shindoh, Y. Takemoto and K. Takasu, Chem.–Eur.
J., 2009, 15, 12168.
2 A. Franc¸ ais, D. Urban and J.-M. Beau, Angew. Chem., Int. Ed.,
2007, 46, 8662.
3 C.-C. Wang, J.-C. Lee, S.-Y. Luo, S. S. Kulkarni, Y.-W. Huang,
C.-C. Lee, K.-L. Chang and S.-C. Hung, Nature, 2007, 446, 896.
4 For some other recent one-pot tandem procedures, see:
(a) Y. Vohra, M. Vasan, A. Venot and G.-J. Boons, Org. Lett.,
2008, 10, 3247; (b) K.-K. T. Mong, C.-S. Chao, M.-C. Chen and
C.-W. Lin, Synlett, 2009, 603; (c) R. A. Jones, R. Davidson,
A. T. Tran, N. Smith and M. C. Galan, Carbohydr. Res., 2010,
345, 1842; (d) H.-C. Lin, Y. B. Chen, Z. P. Lin, F. F. Wong,
C.-H. Lin and S.-K. Lin, Tetrahedron, 2010, 66, 5229.
5 For selected reviews see: (a) C. Bolm, J. Legros, J. Le Paih and
L. Zani, Chem. Rev., 2004, 104, 6217; (b) D. Diaz, P. Miranda,
J. Padron and V. Martın, Curr. Org. Chem., 2006, 10, 457;
´ ´
c
2148 Chem. Commun., 2011, 47, 2146–2148
This journal is The Royal Society of Chemistry 2011