2264
O. Nguyen Van Buu et al. / Tetrahedron 65 (2009) 2260–2265
(IR, H and 13C) were identical to the initial ionic liquid sample. This
1
4.2.5.1. 3-Methyl-1-(3R,3aR,6S,6aR)-[6-(acetoxy)-hexahydrofuro[3,2-
b]furan-3-yl]imidazolium trifluoromethanesulfonate 11. Yield: 46%;
IL was reused without loss of efficiency (Table 1, entry 2).
2
5
[
2
(
a
]
D
þ82.0 (c 0.65, acetone); IR (neat)
888, 1739, 1580, 1558, 1375, 1258, 1164, 1030, 639 cm ; H NMR
360 MHz, MeOD-d 2.11 (s, 3H), 3.95 (s, 3H), 3.99–4.01 (m, 2H),
n
¼3521, 3156, 3120, 2984,
ꢂ1
1
4.2.7.1. (2S)-2,3-Dihydro-2-phenyl-1-[(R)-1-phenylethyl]pyridine-4-
ꢀ
26
4
)
d
(1H)-one 17. Mp: 74 C; [
a
]
D
þ183.7 (c 1.96, CHCl
3
) (de¼97% de-
4
.05 (t, J¼9.2 Hz, 1H), 4.34 (dd, J¼9.0 and 6.8 Hz, 1H), 4.71 (t,
termined by chiral HPLC); IR (neat): 3029, 2975, 1639, 1590, 1494,
1451, 1393, 1294, 1152, 762, 700 cm
ꢂ1
1
J¼4.9 Hz, 1H), 4.67 (t, J¼5.0 Hz, 1H), 5.02–5.08 (m, 1H), 5.26 (q,
J¼4.9 Hz, 1H), 7.58 (t, J¼1.8 Hz, 1H), 7.70 (t, J¼1.8 Hz, 1H), 9.04 (s,
;
H NMR (CDCl 1.45 (d,
3
) d
3H, J¼6.8 Hz), 2.55–2.88 (m, 2H), 4.43 (q, 1H, J¼6.8 Hz), 4.70 (dd,
13
1
6 3 3
H); C NMR (75 MHz, acetone-d ) d 20.5 (CH ), 36.7 (CH ), 62.1
1H, J¼6.8 and 8.8 Hz), 5.04 (d, 1H, J¼7.0 Hz), 7.06 (d, 1H, J¼7.0 Hz),
13
(
(
[
CH), 70.2 (CH
2CH), 137.9 (CH), 170.8 (Cq); HRMS (MꢂOTf) m/z (%) calcd for
]: 253.1183, found: 253.1185.
2
), 72.6 (CH
2
), 75.0 (CH), 81.5 (CH), 83.0 (CH), 124.0
3 3 2
7.09–7.42 (m, 10H); C NMR (CDCl ) d 17.4 (CH ), 43.2 (CH ), 59.0
(CH), 60.2 (CH), 98.0 (CH), 125.8, 126.4, 127.3, 128.0, 128.3, 128.8
C
12
H
17
N
2
O
4
(10CHAr), 138.7 (C), 139.6 (C), 149.0 (CH), 189.8 (C); HRMS (EI) calcd
þ
for C19
H
19NO (M ): 277.1461, found: 277.1460.
4.2.5.2. 2,3-Dimethyl-1-(3R,3aR,6S,6aR)-[6-(acetoxy)-hexahydrofuro
[
5
2
(
3
1
7
3,2-b]furan-3-yl]imidazolium trifluoromethanesulfonate 13. Yield:
4.2.7.2. (2R)-2,3-Dihydro-2-phenyl-1-[(R)-1-phenylethyl]pyridine-4-
25
0%; [
890, 1591, 1532, 1374, 1739, 1259, 1163, 1031, 639 cm
2.10 (s, 3H), 2.69 (s, 3H), 3.84 (s, 3H), 3.84–
a
]
D
þ131.7 (c 0.50, acetone); IR (neat)
n
¼3508, 3147, 2961,
(1H)-one (17 diastereomer). IR (neat): 3029, 2975, 1639, 1590, 1494,
ꢂ1
1
ꢂ1
1
;
H NMR
1451,1393,1294,1152, 762, 700 cm ; H NMR (CDCl ) d 1.60 (d, 3H,
3
360 MHz, MeOD-d
4
)
d
J¼7.0 Hz), 2.55–2.88 (m, 2H), 4.28 (q, 1H, J¼6.8 Hz), 4.70 (dd, 1H,
J¼6.8 and 8.8 Hz), 5.14 (d, 1H, J¼7.5 Hz), 7.61 (d, 1H, J¼7.7 Hz),
.89 (m, 1H), 3.92–3.98 (m, 1H), 4.19–4.29 (m, 2H), 4.80 (t, J¼5.0 Hz,
13
H), 4.88 (t, J¼5.2 Hz, 1H), 5.03–5.09 (m, 1H), 5.19 (q, J¼5.3 Hz, 1H),
3 3 2
7.09–7.42 (m, 10H); C NMR (CDCl ) d 21.4 (CH ), 43.9 (CH ), 59.9
13
.46 (d, J¼2.2 Hz, 1H), 7.62 (d, J¼2.2 Hz, 1H); C NMR (62.5 MHz,
(CH), 60.6 (CH), 99.5 (CH), 125.9, 126.6, 127.8, 128.2, 128.7, 128.9
MeOD-d
5.4 (CH), 82.5 (CH), 83.6 (CH), 121.8 (CH), 123.4 (CH), 147.1 (Cq),
]:
4
)
d
21.0 (CH
3
), 35.9 (CH
3
), 60.9 (CH), 70.8 (CH
2
), 73.0 (CH
2
),
(10CHAr), 139.3 (C), 141.8 (C), 152.0 (CH), 190.4 (C); HRMS (EI) calcd
þ
7
1
2
for C19
H
19NO (M ): 277.1461, found: 277.1460.
71.9 (Cq); HRMS (MꢂOTf) m/z (%) calcd for [C13
19 2 4
H N O
67.1339, found: 267.1345.
Acknowledgements
4
.2.6. General procedure for the synthesis of compounds 8 and 14
Concentrated HCl (2 drops) were added to a solution of acetate
1 (or 13) (3.6 mmol) in ethanol (60 mL). The mixture was heated in
reflux for 4 h. After cooling, the reaction mixture was neutralized
with a solution of saturated Na CO . Solvents were evaporated and
the residue was dissolved in acetone. The organic phase was dried
over anhydrous MgSO , filtered and evaporated. The crude product
was purified by flash chromatography alumina (CH Cl then
CH Cl /MeOH gradually from 5% to 20%) to give 8 (or 14) as a yellow
oil.
We are grateful to the ‘Minist e` re de l’Enseignement Sup e´ rieur et
de la Recherche’ for a doctoral fellowship to O.N.V.B., the CNRS
1
(
UMR 8182) and the Universit e´ Paris-Sud 11 for financial supports.
2
3
References and notes
4
1
. (a) Welton, T. Chem. Rev. 1999, 2071; (b) Wasserscheid, P.; Keim, W. Angew.
Chem., Int. Ed. 2000, 39, 3772; (c) Hagiwara, R.; Ito, Y. J. Fluorine Chem. 2000, 105,
21; (d) Rogers, R. D.; Seddon, K. R. Ionic Liquids Industrial Applications to Green
2
2
2
2
2
Chemistry. ACS Symposium Series; 2001; Vol. 818; (e) Wasserscheid, P.; Welton,
T. Ionic Liquids in Synthesis; Wiley-VCH: Weinheim, 2002; (f) Dupont, J.; de
Souza, R. F.; Suarez, P. A. Z. Chem. Rev. 2002, 102, 3667; (g) Sheldon, R. A. Green
Chem. 2005, 267.
4
.2.6.1. 3-Methyl-1-(3R,3aR,6S,6aR)-[6-(hydroxy)-hexahydrofuro[3,2-
2
. (a) Ding, J.; Armstrong, D. W. Chirality 2005, 17, 281; (b) Baudequin, C.; Br e´ geon,
D.; Levillain, J.; Guillen, F.; Plaquevent, J.-C.; Gaumont, A.-C. Tetrahedron:
Asymmetry 2005, 16, 3921; (c) Chen, X.; Li, X.; Hu, A.; Wang, F. Tetrahedron:
Asymmetry 2008, 19, 1; (d) Bica, K.; Gaertner, P. Eur. J. Org. Chem. 2008, 3235.
. (a) P e´ got, B.; Vo-Thanh, G.; Gori, D.; Loupy, A. Tetrahedron Lett. 2004, 45, 6425;
b]furan-3-yl]imidazolium trifluoromethanesulfonate 8. Yield: 90%.
4
.2.6.2. 2,3-Dimethyl-1-(3R,3aR,6S,6aR)-[6-(hydroxy)-hexahydrofuro
3
[3,2-b]furan-3-yl]imidazolium trifluoromethanesulfonate 14. Yield:
(b) Ding, J.; Desikan, V.; Han, X.; Xiao, T. L.; Ding, R.; Jenks, W. S.; Armtrong, D.
2
0
9
2
0%; [
888, 1634, 1591, 1538, 1423, 1253, 1170, 1032, 758, 639 cm
2.66 (s, 3H, H
), 3.49 (dd, J¼9.0 and
), 3.82–3.86 (m, 1H, H ), 3.84 (s, 3H, H ), 4.23–4.38 (m,
), 4.83 (t, J¼5.2 Hz,1H, H ), 5.10 (q,
), 7.46 (d, J¼2.2 Hz,1H, H ), 7.65 (d, J¼2.0 Hz,1H, H
10.1 (CH ), 35.6 (CH ), 61.9 (CH), 71.4
), 82.8 (CH), 84.9 (CH), 121.4 (CH), 123.3
]:
a
]
D
þ112.3 (c 0.50, acetone); IR (neat)
n
¼3479, 3148, 2960,
W. Org. Lett. 2005, 7, 335; (c) Wang, Z.; Wang, Q.; Zhang, Y.; Bao, W. Tetrahedron
Lett. 2005, 46, 4657; (d) Luo, S.; Mi, X.; Zhang, L.; Liu, S.; Xu, H.; Cheng, J.-P.
Angew. Chem., Int. Ed. 2006, 45, 3093; (e) Gausepohl, R.; Buskens, P.; Kleinen, J.;
Bruckmann, A.; Lehmann, C. W.; Klankermayer, J.; Leitner, W. Angew. Chem., Int.
Ed. 2006, 45, 3689; (f) Branco, L. C.; Gois, P. M. P.; Lourenço, N. M. T.; Kurteva, V.
B.; Afonso, C. A. M. Chem. Commun. 2006, 2371; (g) Malhotra, S. V.; Wang, Y.
Tetrahedron: Asymmetry 2006, 17, 1032; (h) P a´ d a´ r, P.; Bokros, A.; Paragi, G.;
Forg o´ , P.; Kele, Z.; Howarth, N. M.; Kov a´ cs, L. J. Org. Chem. 2006, 8669; (i) P e´ got,
B.; Nguyen Van Buu, O.; Gori, D.; Vo-Thanh, G. Beilstein J. Org. Chem. 2006, 2, 18;
(j) Zhou, L.; Wang, L. Chem. Lett. 2007, 36, 628; (k) Ni, B.; Zhang, Q.; Headley, A.
D. Green Chem. 2007, 9, 737; (l) Nguyen Van Buu, O.; Vo-Thanh, G. Lett. Org.
Chem. 2007, 4, 158; (m) Yadav, L. D. S.; Rai, A.; Rai, V.; Awasthi, C. Tetrahedron
ꢂ1
1
;
H
NMR (360 MHz, MeOD-d
.6 Hz, 1H, H
4
)
d
m
7
3
f
f
k
H, Hcþe), 4.58 (t, J¼4.9 Hz,1H, H
d
a
13
J¼6.1 Hz, H
b
i
j
);
C
NMR (90 MHz, MeOD-d
4
)
d
3
3
(
(
2
2 2
CH ), 73.3 (CH), 74.2 (CH
CH), 147.1 (CH); HRMS (MꢂOTf) m/z (%) calcd for [C11
17 2 3
H N O
25.1234, found: 225.1241.
2008, 64, 1420; (n) Zhou, W.; Xu, L. W.; Qiu, H. Y.; Lai, G. Q.; Xia, C. G.; Jiang, J. X.
Helv. Chim. Acta 2008, 91, 53.
4
. (a) Biedtron, T.; Kubisa, P. Polym. Int. 2003, 52, 1584; (b) Ma, H.-Y.; Wan, X.-H.;
Chen, X.-F.; Zhou, Q. F. Chin. J. Polym. Sci. 2003, 21, 265; (c) Biedtron, T.; Kubisa,
P. J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 3454.
4
.2.7. General procedure for the asymmetric aza Diels–Alder
reaction of Danishefsky’s diene with imine 22
A mixture of imine 16 (1 mmol), chiral ionic liquid (0.5 equiv)
and Danishefsky’s diene 15 (1.5 equiv added in three portions) was
stirred at 30 C for 5 h. The reaction mixture was extracted from the
5. (a) Ding, J.; Welton, T.; Armstrong, D. W. Anal. Chem. 2004, 76, 6819; (b) Rizvi,
S. A. A.; Shamsi, S. A. Anal. Chem. 2006, 78, 7061.
ꢀ
6. (a) Tosoni, M.; Laschat, S.; Baro, A. Helv. Chim. Acta 2004, 87, 2742; (b) Baudoux,
J.; Judeinstein, P.; Cahard, D.; Plaquevent, J.-C. Tetrahedron Lett. 2005, 46, 1137.
7. (a) Wasserscheid, P.; Bosmann, A.; Bolm, C. Chem. Commun. 2002, 200; (b) Ishida,
Y.; Miyauchi, H.; Saigo, K. Chem. Commun. 2002, 2240; (c) Levillain, J.; Dubant, G.;
Abrunhosa, I.; Gulea, M.; Gaumont, A.-C. Chem. Commun. 2003, 2914; (d) Clavier,
H.; Boulanger, L.; Audic, N.; Toupet, L.; Mauduit, M.; Guillemin, J.-C. Chem.
Commun. 2004, 1224; (e) Ishida, Y.; Sasaki, D.; Miyauchi, H.; Saigo, K. Tetrahedron
2004, 45, 9455; (f) Jurcik, V.; Wilhelm, R. Tetrahedron: Asymmetry 2006, 17, 801.
ionic liquid phase with Et
tions were dried over anhydrous MgSO
2
O (3ꢁ10 mL). The combined ether frac-
4
and evaporated under
reduced pressure. The residue was purified by flash column chro-
matography (AcOEt/pentane¼10:90 to 70:30) to provide 17.
The chiral ionic liquid was dissolved in dichloromethane
8
9
. Kagan, H. B.; Riant, O. Chem. Rev. 1992, 92, 1007.
. Sheldon, R. A. Chirotechnology: Industrial Synthesis of Optically Active Com-
pounds; Marcel Dekker: New York, NY, 1993; p 145.
(
20 mL) and then recycled by washing with water (10 mLꢁ2). The
organic phase was dried over anhydrous MgSO , filtered and
evaporated in vacuo to afford the recycled ionic liquid. Spectra data
4
10. Krantz, J. C.; Carr, C. J.; Forman, S. E.; Ellis, F. W. J. Pharmacol. 1939, 67, 191.