Synthesis of spiroacetal enol ethers via intramolecular conjugate addition of hemiacetal alkoxides to alkynoates

Tetrahedron Letters

Volumn 37, Issue 32, 1996, Pages 5707-5710

  Toshima, Hiroaki ^a   Furumoto, Yoshinori ^a   Inamura, Shintaro ^a   Ichihara, Akitami ^a  

^a HOKKAIDO UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

ACETAL DERIVATIVE; ALKYNE DERIVATIVE; FURAN DERIVATIVE; SPIRO COMPOUND; TETRAHYDROPYRAN DERIVATIVE;

ARTICLE; CHIRALITY; DRUG SYNTHESIS; NUCLEAR MAGNETIC RESONANCE; REACTION ANALYSIS;

EID: 0030570912     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)01206-3     Document Type: Article

References (20)

1. 1. (a) Bohlmann, F.; Burkhardt, T.; Zdero, C. Naturally Occurring Acetylenes; Academic Press: London, 1973.
2. (b) Christensen, L. P. Phytochemistry 1992, 31, 7-49.
3. 2. (a) Wurz, G.; Hofer, O.; Sanz-Cervera, J. F.; Marco, J. A. Liebigs Ann. Chem. 1993, 99-101.
4. (b) Birnecker, W.; Wallnofer, B.; Hofer, O.; Greger, H. Tetrahedron 1988, 44, 267-276.
5. (c) Bohlmann, F.; Rode, K. M. Chem. Ber. 1966, 99, 2416-2418.
6. 3. (a) Martinez, V.; Barbera, O.; Sanchez-Parareda, J.; Marco, J. A. Phytochemistry 1987, 26, 2619-2624.
7. (b) Breinlich, J.; Scharnagel, K. Arzneim-Forsch. 1968, 18, 429-431.
8. (c) Tada, M.; Chiba, K. Agric. Biol. Chem. 1984, 48, 1367-1369.
9. 4. (a) Bohlmann, F.; Jastrow, H.; Ertingshausen, G.; Kramer, D. Chem. Ber. 1964, 97, 801-808.
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11. (c) Gao, Y.; Wu, W.-L.; Ye, B.; Zhou, R.; Wu, Y.-L. Tetrahedron Lett. 1996, 37, 893-896.
12. 5. There are many synthetic studies on monocyclic enol ethers and lactones starting from acetylenic alcohols and carboxylic acids, respectively. Several examples are shown in following: (a) Grandjean, D.; Pale, P.; Chuche, J. Tetrahedron Lett. 1992, 33, 4905-4908.
13. (b) Pale, P.; Chuche, J. Tetrahedron Lett. 1987, 28, 6447-6448.
14. (c) Dai, W.; Katzenellenbogen, J. A. J. Org. Chem. 1991, 56, 6893-6896.
15. (d) Arcadi, A.; Burini, A.; Cacchi, S.; Delmastro, M.; Marinelli, F.; Pietroni, B. R. J. Org. Chem. 1992, 57, 976-982.
16. (e) Pflieger, D.; Muckensturm, B. Tetrahedron 1989, 45, 2031-2040.
17. 6. Satisfactory spectroscopic data were obtained for all new compounds.
18. 7. When 10 was treated with anhydrous TBAF in THF, furan 12a was obtained in 30-50% yield. A similar anionic cyclization (using NaH) starting from keto alkynoates to give furan derivatives has recently been reported. (Vieser, R.; Eberbach, W. Tetrahedron Lett. 1995, 36, 4405-4408.) (formula presented)
19. 8. In ref. 5e, the authors explain that the geometrical selectivity (Z/E = 10/90) can be related to the steric hindarance between the furanoic oxygen and the ester function.
20. 9. After dethioacetalization of 21, the following acid treatment provided spiroacetal enol ethers 22E and 22Z in one pot. The low yield may be due to the volatility of the products. (formula presented)