T. Ohgiya, S. Nishiyama / Tetrahedron Letters 45 (2004) 8273–8275
8275
Scheme 3. Reagents and conditions: (a) concd HCl, EtOH, 50°C (80%). (b) (ꢀ)-DET, TBHP, Ti(OiPr)4, CH2Cl2, ꢀ30°C (99%). (c) TBDPSCl, Imd,
DMF, rt (100%). (d) LiEt3BH, THF, 60°C (94%; 16:17 = 1:1). (e) PCC, MS4A, CH2Cl2, 0°C (60%; 18:19 = 6:1). (f) TBAF, THF, rt (87%).
Watanabe, M.; Honda, T. Tetrahedron 2002, 58, 8929–
8936; (d) Carda, H.; Rodriguez, S.; Castillo, E.; Bellido, A.;
Diaz-Oltra, S.; Marco, J. A. Tetrahedron 2003, 59, 857–
864; (e) Koumbis, A. E.; Dieti, K. M.; Vikentiou, M. G.;
Gallos, J. K. Tetrahedron Lett. 2003, 44, 2513–2516; (f)
Schomaker, J. M.; Borhan, B. Org. Biomol. Chem. 2004, 2,
621–624.
which underwent lactonization with PCC to give a 6:1
mixture of the six-membered ring lactone 18 and the
seven-membered ring lactone 19 in 60% yield. Finally,
treatment of the mixture with TBAF afforded (+)-1 in
22
25
87% yield, ½aꢁ +1.9 (c 1.0, CHCl3) {lit.,1 ½aꢁ +2.3 (c
D
D
0.65, CHCl3)}. The synthetic (+)-1 was identical to the
natural product under the full range of spectroscopic
data.1
4. Ohgiya, T.; Nishiyama, S. Chem. Lett. 2004, 33, 1084–1085.
5. Negishi, E.; Valente, L. F.; Kobayashi, M. J. Am. Chem.
Soc. 1980, 102, 3298–3299.
In conclusion, the total synthesis of (+)-1, a toxic and
antifungal metabolite, was accomplished by utilizing
our efficient and simple bromoalkene synthesis by the
regioselective HBr elimination reaction. As demon-
strated, our approach is applicable to other congeners.
Further investigation is in progress.
6. (a) Finn, M. G.; Sharpless, K. B. In On the Mechanism of
Asymmetric Epoxydation with Titanium-Tartrate Catalysts.
Asymmetric Synthesis; Morrison, J. D., Ed.; Academic:
Tokyo, 1985; Vol. 5, pp 247–308; (b) Katsuki, T.; Sharpless,
K. B. J. Am. Chem. Soc. 1980, 102, 5974–5976.
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102, 4730–4743; (b) Trost, B. M.; Asakawa, N. Synthesis
1999, 1491–1494.
References and notes
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Hartung, J.; Kawanami, Y.; Lubben, D.; Manoury, E.;
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L.; Crispino, G. A.; Hartung, J.; Jeong, K.-S.; Kwong, H.-
L.; Morikawa, K.; Wang, Z.-M.; Xu, D.; Zhang, X.-L. J.
Org. Chem. 1992, 57, 2768–2771.
1. Singh, I. P.; Milligan, K. E.; Gerwick, W. H. J. Nat. Prod.
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3. (a) Kanada, R. M.; Taniguchi, T.; Ogasawara, K. Synlett
2000, 1019–1021; (b) Tanaka, H.; Kozuki, Y.; Ogasawara,
K. Tetrahedron Lett. 2002, 43, 4175–4178; (c) Mizutani, H.;
1
9. The optical purity was determined by 400MHz H NMR
spectra of the corresponding MTPA ester.