484
J. LI AND L. LIU
homogeneous Lewis acids in the Diels–Alder reaction. Tetrahedron Lett. 1997, 38, 3097–
3100; (c) Earle, M. J.; McCormac, P. B.; Seddon, K. R. Diels–Alder reactions in ionic
liquids. Green Chem. 1999, 1, 23–25; (d) Ni, B.; Headley, A. D. Ionic-liquid-supported
(ILS) catalysts for asymmetric organic synthesis. Chem. Eur. J. 2010, 16, 4426–4436; (e)
Luo, S.; Zhang, L.; Cheng, J. P. Functionalized chiral ionic liquids: A new type of asym-
metric organocatalysts and nonclassical chiral ligands. Asian J. 2009, 4, 1184–1195.
´
3. (a) Pegot, B.; Vo-Thanh, G.; Gori, D.; Loupy, A. First application of chiral ionic liquids
in asymmetric Baylis–Hillman reaction. Tetrahedron Lett. 2004, 45, 6425–6428; (b)
Gausepohl, R.; Buskens, P.; Kleinen, J.; Bruckmann, A.; Lehmann, C. W.; Klankermayer,
J.; Leitner, W. Highly enantioselective aza-Baylis–Hillman reaction in a chiral reaction
medium. Angew. Chem. Int. Ed. 2006, 45, 3689–3692.
4. (a) Wu, L. Y.; Yan, Z. Y.; Xie, Y. X.; Niu, Y. N.; Liang, Y. M. Ionic-liquid-supported
organocatalyst for the enantioselective Michael addition of ketones to nitroolefins. Tetra-
hedron: Asymmetry 2007, 18, 2086–2090; (b) Xu, D. Q.; Wang, B. T.; Luo, S. P.; Yue, H.
D.; Wang, L. P.; Xu, Z. Y. Pyrrolidine–pyridinium-based organocatalysts for highly enan-
tioselective Michael addition of cyclohexanone to nitroalkenes. Tetrahedron: Asymmetry
2007, 18, 1788–1794; (c) Maltsev, O. V.; Kucherenko, A. S.; Beletskaya, I. P.;
Tartakovsky, V. A.; Zlotin, S. G. Chiral ionic liquids bearing O-silylated a,a -diphenyl(S)-
or (R)-prolinol units: Recoverable organocatalysts for asymmetric Michael addition of
nitroalkanesto a,b-enals. Eur. J. Org. Chem. 2010, 2927–2933.
5. (a) Miao, W. S.; Chan, T. H. Ionic-liquid-supported organocatalyst: Efficient and recyclable
ionic-liquid-anchored proline for asymmetric aldol reaction. Adv. Synth. Catal. 2006, 348,
1711–1718; (b) Siyutkin, D. E.; Kucherenko, A. S.; Struchkova, M. I.; Zlotin, S. G. A novel
(S)-proline-modified task-specific chiral ionic liquid—An amphiphilic recoverable
catalyst for direct asymmetric aldol reactions in water. Tetrahedron Lett. 2008, 49,
1212–1216.
6. (a) Ishii, T.; Fujioka, S.; Sekiguchi, Y.; Kotsuki, H.
A new class of chiral
pyrrolidine-pyridine conjugate base catalysts for use in asymmetric Michael additionreac-
tions. J. Am. Chem. Soc. 2004, 126, 9558–9559 (b) Wang, W.; Wang, J.; Li, H. Highly
enantioselective pyrrolidine sulfonamide–catalyzed Michael addition of aldehydes to
nitrostyrenes. Angew. Chem. Int. Ed. 2005, 44, 1369–1371; (c) Hayashi, Y.; Gotoh, H.;
Hayashi, T.; Shoji, M. Diphenylprolinol silyl ethers as efficient organocatalysts for the
asymmetric Michael reaction of aldehydes and nitroalkenes. Angew. Chem. Int. Ed.
2005, 44, 4212–4215; (d) Pansare, S. V.; Pandya, K. Simple diamine- and
triamine-protonic acid catalysts for the enantioselective Michael addition of cyclic ketones
to nitroalkenes. J. Am. Chem. Soc. 2006, 128, 9624–9625; (e) Cao, C.-L.; Ye, M.-C.; Sun,
X.-L.; Tang, Y. Pyrrolidine–thiourea as a bifunctional organocatalyst: Highly enantiose-
lective Michael addition of cyclohexanone to nitroolefins. Org. Lett. 2006, 8, 2901–2904;
(f) Singh, V. K.V. Highly enantioselective water-compatible organocatalyst for Michael
reaction of ketones to nitroolefins. Org. Lett. 2007, 9, 1117–1119.
7. (a) List, B.; Pojarliev, P.; Martin, H. J. Efficient proline-catalyzed Michael additions of
unmodified ketones to nitro olefins. Org. Lett. 2001, 3, 2423–2425; (b) Enders, D.; Seki,
A. Proline-catalyzed enantioselective Michael additions of ketones to nitrostyrene. Syn-
lett. 2002, 1, 26–28; (c) Betancort, J. M.; Barbas III, C. F. Catalytic direct asymmetric
Michael reactions: Taming naked aldehyde donor. Org. Lett. 2001, 3, 3737–3740.
8. (a) Zhang, B. N.; Headley, A. D. Asymmetric Michael addition reactions of aldehydes
with nitrostyrenes catalyzed by functionalized chiral ionic liquids. Tetrahedron 2008, 64,
5091–5097; (b) Luo, S.; Mi, X.; Liu, S.; Xu, P. L.; Cheng, J.-P. Surfactant-type asymmet-
ric organocatalyst: Organocatalytic asymmetric Michael addition to nitrostyrenes in
water. Chem. Commun. 2006, 3687–3689; (c) Ni, B.; Zhang, Q.; Dhungana, K.;
Headley, A. D. Ionic liquid–supported (ILS) (S)-pyrrolidine sulfonamide, a recyclable