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(4) (a) Ogawa, A.; Curran, D. P. J. Org. Chem. 1997, 62, 450.
(b) Nishikido, J.; Nakajima, H.; Saeki, T.; Ishii, A.; Mikami,
K. Synlett 1998, 1347.
Acknowledgement
This work was financially supported by the Institute of Science and
Engineering, Chuo University, Special Project Research “Develop-
ment of Green Chiral Technology”. We are grateful to Professor
Toshitaka Funazukuri, Chuo University, for his advice in setting up
the supercritical carbon dioxide reactor and useful comments on the
reaction.
(5) (a) For a review: For supercritical fluid in organic synthesis,
Jessop, P. G.; Ikariya, T.; Noyori, N. Chem. Rev. 1999, 99,
475. (b) For examples of scandium salts catalyzed reactions in
scCO2. Oakes, R. S.; Heppenstall, T. J.; Shezad, N.; Clifford,
A. A.; Ranyner, C. M. Chem. Commum. 1999, 1459; Matsuo,
J. -i.; Tsuchiya, T.; Odashima, K.; Kobayashi, S. Chem. Lett.
2000, 178; Kawada, A.; Mitamura, S.; Matsuo, J. -i.;
Tsuchiya, T.; Kobayashi, S. Bull. Chem. Soc. Jpn. 2000, 73,
2325.
(6) Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and
Practice; Oxford University Press: Oxford, 1998.
(7) A commercial product (Aldrich).
(8) Takahashi, H.; Kawakita, T.; Ohno, M.; Yoshioka, M.;
Kobayashi, S. Tetrahedron 1992, 48, 5691.
References and Notes
(1) (a) Kobayashi S. In Sc (III) Lewis Acids; Lewis Acids in
Organic Synthesis; Yamamoto, H., Ed; VCH: Weinheim,
2000; Vol 2, Chapter 19. (b) Shibasaki M.; Yamada, K.;
Yoshikawa, N In Lanthanide Lewis Acids Catalysis; Lewis
Acids in Organic Synthesis; Yamamoto, H., Ed; VCH:
Weinheim, 2000; Vol 2, Chapter 20. (c) Fukuzawa, S. In
Scandium (III) and Yttrium (III); Lewis Acids Reagents;
Yamamoto, H., Ed; Oxford University Press: Oxford, 1999,
pp 185-203. (d) Nakai, T.; Tomooka, K. In Lanthanide (III)
Reagents; Yamamoto, H., Ed; Lewis Acids Reagents; Oxford
University Press: Oxford, 1999, pp 204-223. e) Lanthanides:
Chemistry and Use in Organic Synthesis; Kobayashi, S., Ed.;
Topics in Organometallic Chemistry; Springer: Heiderberg,
1999.
(2) Some asymmetric reactions using REX3/pybox complex have
been reported while our work was in progress. (a) Sanchez-
Blanco, A. I.; Gothelf, K. V.; J rgensen, K. A. Tetrahedron
Lett. 1997. 38, 7923. (b) Aspinall, H. C.; Greeves, N.; Smith,
P. M. Tetrahedron Lett. 1999, 40, 1763. (c) Schaus, S. E.;
Jacobsen, E. N. Org. Lett. 2000, 2, 1001. (d) Qian, C.; Wang,
L. Tetrahedron Lett. 2000, 41, 2203. (e) Qian, C.; Wang, L.
Tetrahedron: Asymmetry 2000, 11, 2347.
(9) Irie, R.; Noda, K.; Ito, Y.; Matsumoto, N.; Katsuki, T.
Tetrahedron: Asymmetry 1991, 2, 481.
(10) Hanamoto, T.; Sugimoto, Y.; Jin, Y. Z.; Inanaga, J. Bull.
Chem. Soc. Jpn. 1997, 70, 1421.
(11) For examples for Ln(NTf2)3-catalyzed organic reactions:
(a) Kobayashi, H.; Nie, J.; Sonoda, T. Chem. Lett. 1995, 307.
(b) Ishihara, K.; Kubota, M.; Yamamoto, H. Synlett 1996, 265.
(c) Ishihara, K.; Karumi, Y.; Kubota, M.; Yamamoto, H.
Synlett 1996, 839. (d) Mikami, K.; Kotera, O.; Motoyama, Y.;
Sakaguchi, H.; Maruta, M. Synlett 1996, 171.
(12) Kobayashi et al. have reported that the Sc(OTf)3/(R)-BINOL
complex is an effective catalyst for asymmetric Diels-Alder
reaction, however they have never showed the reaction with
the acryloyl dienophile 1a.1a,1e
(13) Asymmetric Diels-Alder reaction with chiral dienophiles in
scCO2 will be reported in due course.
(14) Black, H.; Environ. Sci. Tecknol. 1996, 30, 124A.
(3) For a review of catalytic asymmetric Diels-Alder reaction, see
(a) Kagan, H. B.; Riant, O. Chem. Rev. 1992, 92, 1007.
(b) Evans, D. A.; Johnson, J. S. In Diels-Alder Reaction;
Comprehensive Asymmetric Catalysis; Jacobsen, E. N.;
Pfalts, A.; Yamamoto, H., Eds; Springer: Berlin, 1999; Vol
III, Chapter 33.1.
Article Identifier:
1437-2096,E;2001,0,05,0709,0711,ftx,en;Y05501ST.pdf
Synlett 2001, No. 5, 709–711 ISSN 0936-5214 © Thieme Stuttgart · New York