9244
T. Satoh et al. / Tetrahedron Letters 42 (2001) 9241–9244
cyanomethyllithium in the same way as described above
to obtain the desired enaminonitrile (−)-15 in 97% yield
with better ee (99.2% ee) than the case of (S)-(−)-10.
Booker-Milburn, K. I.; Sharpe, A. J. Chem. Soc., Perkin
Trans. 1 1998, 983.
2. (a) Blumenkopf, T. A.; Overman, L. E. Chem. Rev. 1986,
86, 857; (b) Habermas, K. L.; Denmark, S. E.; Jones, T.
K. Org. React. 1994, 45, 1.
3. (a) Pauson, P. L. Tetrahedron 1985, 41, 5855; (b) Schore,
N. E. Org. React. 1991, 40, 1; (c) Brummond, K. M.;
Kent, J. L. Tetrahedron 2000, 56, 3263; (d) Perez-Serrano,
L.; Blanco-Urgoiti, J.; Casarrubios, L.; Dominguez, G.;
Perez-Castells, J. J. Org. Chem. 2000, 65, 3513 and
references cited therein.
4. (a) Geis, O.; Schmalz, H.-G. Angew. Chem., Int. Ed.
1998, 37, 911; (b) Kerr, W. J.; Lindsay, D. M.; Rankin,
E. M.; Scott, J. S.; Watson, S. P. Tetrahedron Lett. 2000,
41, 3229; (c) Hiroi, K.; Watanabe, T. Tetrahedron Lett.
2000, 41, 3935.
The enaminonitrile (−)-15 was heated in the solution of
phosphoric acid in acetic acid to give the enone (−)-16
in 83% yield. Comparing the sign of specific rotation of
the enone (−)-16 with that of the reported optically
active 16,9 the absolute configuration of the enone was
determined to be S. The result from the vinyl sulfoxide
14 is shown in Scheme 5. Again, the asymmetric induc-
tion is explained by the chelated model shown in
Scheme 4.
It is worth noting that the asymmetric induction men-
tioned in this paper is one of the highest in the asym-
metric synthesis using chiral sulfoxide. Investigation of
the scope and limitation of this asymmetric synthesis
and applications to synthesis of natural products are
underway in this laboratory.
5. (a) Martin, S. F. Tetrahedron 1980, 36, 419; (b) Fuji, K.
Chem. Rev. 1993, 93, 2037; (c) Corey, E. J.; Guzman-
Perez, A. Angew. Chem., Int. Ed. 1998, 37, 388.
6. (a) Satoh, T.; Ota, H. Tetrahedron 2000, 56, 5113; (b)
Satoh, T.; Takano, K.; Ota, H.; Someya, H.; Matsuda,
K.; Koyama, M. Tetrahedron 1998, 54, 5557.
7. Satoh, T.; Sato, T.; Ohara, T.; Ueda, Y.; Yamakawa, K.
Acknowledgements
J. Org. Chem. 1989, 54, 3130.
8. HPLC analysis of racemic 10 using a chiral column
(Daisel CHIRALCEL OD, 10% 2-isopropanol in hexane)
showed clear base-line separation of both enantiomers.
9. Riviere, P.; Mauvais, A.; Winterfeldt, E. Tetrahedron:
Asymmetry 1994, 5, 1831. The authors of this paper
reported the value of specific rotation of (S)-(−)-11, −72.5
and (S)-(−)-16, −30.6. These values are much smaller
than our values. The authors did not mention the ee of
these enones in their paper.
This work was supported by a Grant-in-Aid for Scien-
tific Research No. 11640545 from the Ministry of Edu-
cation, Science, Sports, and Culture, Japan, which is
gratefully acknowledged.
References
10. Some recent reviews for the sulfoxide-mediated asymmet-
ric synthesis: (a) Walker, A. J. Tetrahedron: Asymmetry
1992, 3, 961; (b) Carreno, M. C. Chem. Rev. 1995, 95,
1717; (c) Aversa, M. C.; Barattucci, A.; Bonaccorsi, P.;
Giannetto, P. Tetrahedron: Asymmetry 1997, 8, 1339; (d)
Iwata, C. Yakugaku Zasshi 1999, 119, 126.
1. Some recent reviews and a monograph for construction
of cyclic compounds including cyclopentenones: (a) Ho,
T.-L. Carbocyclic Construction in Terpene Synthesis;
VCH Publishers: Weinheim, 1988; (b) Thebtaranonth, C.;
Thebtaranonth, Y. Tetrahedron 1990, 46, 1385; (c) Peta-
sis, N. A.; Patane, M. A. Tetrahedron 1992, 48, 5757; (d)