Scheme 6 Reagents: i, LiHMDS (1.3 equiv.), THF, Ϫ78 ЊC, then 4; ii, CH3SO2Cl, DMAP, CH2Cl2; iii, H2, 10% Pd-C, AcOEt; iv, Na[PhSeB(OEt)3],
AcOH, EtOH; v, 1 M HCl, THF, 0 ЊC.
3 Y. Kono, S. Takeuchi, A. Kawarada, J. M. Daly and H. W. Knoche,
Tetrahedron Lett., 1980, 21, 1537; Y. Kono, S. Takeuchi,
A. Kawarada, J. M. Daly and H. W. Knoche, Agric. Biol. Chem.,
1980, 44, 2613; Y. Kono, S. Takeuchi, A. Kawarada, J. M. Daly
and H. W. Knoche, Bioorg. Chem., 1981, 10, 206.
4 J. M. Daly, Y. Kono, Y. Suzuki and H. W. Knoche, in Pesticide
Chemistry, ed. J. Miyamoto, Pergamon Press, Oxford, 1983, p. 11;
Y. Kono, Y. Suzuki and S. Takeuchi, J. Synth. Org. Chem. Jpn., 1985,
43, 980.
(c 0.35, MeOH); UV λmax 280 nm (ε 108, MeOH); CD λmax 281
nm (∆ε 0.36, MeOH); FD-MS m/z 587 (M ϩ Hϩ), m/z 609
(M ϩ Naϩ), 625 (M ϩ Kϩ). These results are in agreement
with the reported data except melting point 97 ЊC, [α]D25 Ϫ10
(MeOH), UV λmax 275 nm (ε 138, MeOH), CD λmax 281 nm
(∆ε 0.36, MeOH)).2b 1H NMR and 13C NMR spectra of the
synthetic compound were identical with those of natural
PM-toxin B.6,10
In conclusion, the highly stereoselective total synthesis of
PM-toxin B (1) has been achieved by a convergent strategy
involving cross-aldol reactions and the regioselective reductive
cleavage of α,β-epoxy ketone units as key steps.
This work was supported by a Grant-in-Aid for JSPS Fellows
(No. 2709) and a Grant-in-Aid for Scientific Research on
Priority Areas (No. 706: Dynamic Control of Stereochemistry)
from the Ministry of Education, Science, Sports and Culture
of Japan.
5 Y. Suzuki, H. W. Knoche and J. M. Daly, Bioorg. Chem., 1982, 11,
300; Y. Suzuki, S. J. Danko, Y. Kono, S. Takeuchi, J. M. Daly and
H. W. Knoche, Agric. Biol. Chem., 1984, 48, 2321.
6 Y. Suzuki, S. J. Danko, Y. Kono, J. M. Daly and S. Takeuchi,
Agric. Biol. Chem., 1985, 49, 149.
7 H. Hayakawa, M. Ohmori, K. Takamichi, F. Matsuda and
M. Miyashita, Chem. Commun., 1997, 1219.
8 M. Miyashita, T. Suzuki, M. Hoshino and A. Yoshikoshi,
Tetrahedron, 1997, 53, 12469; T. Suzuki and M. Miyashita, J. Synth.
Org. Chem. Jpn., 1998, 56, 736.
9 K.-M. Chen, G. E. Hardtmann, K. Prasad, O. Repic and
M. J. Shapiro, Tetrahedron Lett., 1987, 28, 155.
1
10 H NMR (500 MHz, C5D5N): 0.82 (t, J = 7.0 Hz, 3H), 1.12–1.78
Notes and references
(m, 38H), 1.37 (d, J = 6.2 Hz, 3H), 1.87 (dt, J = 13.8, 9.5 Hz,
1H), 2.54 (t, J = 7.2 Hz, 2H), 2.55 (t, J = 7.3 Hz, 4H), 2.61
(dd, J = 15.0, 4.1 Hz, 1H), 2.62 (dd, J = 15.0, 4.1 Hz, 1H), 2.63
(dd, J = 15.0, 4.1 Hz, 1H), 2.79 (dd, J = 15.0, 8.6 Hz, 2H), 2.81
(dd, J = 15.0, 8.6 Hz, 1H), 4.01–4.12 (m, 1H), 4.24–4.47 (m, 4H);
13C NMR (125 MHz, C5D5N): 210.3, 210.3, 210.3, 71.3, 67.8,
67.7, 67.7, 67.6, 51.3, 51.3, 51.3, 46.5, 43.8, 43.8, 43.8, 38.6, 38.3,
38.1, 38.1, 32.0, 29.6, 29.5, 29.5, 25.9, 25.9, 25.8, 25.7, 24.6, 23.9,
23.9, 23.9, 22.9, 14.1.
1 J. C. Comstock, C. A. Martinson and B. C. Gegenbach, Phyto-
pathology, 1973, 63, 1357; O. C. Yoder, Phytopathology, 1973, 63,
1361.
2 (a) Y. Kono, S. J. Danko, Y. Suzuki, S. Takeuchi and J. M. Daly,
Tetrahedron Lett., 1983, 24, 3803; (b) S. J. Danko, Y. Kono,
J. M. Daly, Y. Suzuki, S. Takeuchi and D. A. McCrery,
Biochemistry, 1984, 23, 759; (c) Y. Kono, Y. Suzuki, S. Takeuchi,
H. W. Knoche and J. M. Daly, Agric. Biol. Chem., 1985, 49, 559.
4230
J. Chem. Soc., Perkin Trans. 1, 2000, 4227–4230