Studies on the acid-catalyzed dimerization of 2-prenylindoles

Tetrahedron

Volumn 52, Issue 28, 1996, Pages 9455-9468

  Lee, Victor ^a,b   Cheung, Man Ki ^a   Wong, Wing Tak ^a   Cheng, Kin Fai ^a  

^a UNIVERSITY OF HONG KONG   (Hong Kong)

^b UNIVERSITY OF OXFORD   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

INDOLE DERIVATIVE;

ARTICLE; CATALYSIS; DIMERIZATION; PRIORITY JOURNAL; REACTION ANALYSIS; X RAY CRYSTALLOGRAPHY;

EID: 0030575346     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4020(96)00482-6     Document Type: Article

References (15)

1. 1. Kong, Y. C.; Ng, K. H.; But, P. P. H.; Li, Q.; Yu, S. X.; Chang, H. T.; Cheng, K. F.; Soejarto, D. D.; Kan, W. S.; Waterman; P. G. J. Ethnopharmacology, 1986, 15, 95.
2. 2. Kong, Y. C.; Cheng, K. F.; Ng, K.H.; But, P.P.H.; Li, Q.; Yu, S.X.; Chang, H.T.; Cambie, R.C.; Kinoshita, T.; Kan, W.S.; Waterman, P.G. Biochem. System Ecol., 1986, 14, 491.
3. 3. Kinoshita; T.; Tatara; S.; Ho; F.C.; Sankawa, U. Phytochemistry, 1989, 8, 147.
4. 4. Cheng, K.F.; Kong, Y.C.; Chan, T.Y. J. Chem. Soc., Chem. Comm., 1985, 48.
5. 5. Sheu, J. H.; Chen, Y.K.; Hong, Y.L.V. Tetrahedron Lett., 1991, 32, 1045.
6. 6. Tillequin, F.; Koch, M.; Pousset, J.L.; Cave, A. J. Chem. Soc, Chem. Comm., 1978, 826.
7. 7. Creary, X.; Geiger, C.S. J. Am. Chem. Soc., 1982, 104, 4158.
8. + = 549) was also isolated from the product mixture (26.3 mg). The molecular weight suggests that it is probably a trimeric indole compound. The proposed mechanism can explain why such a complex product mixture resulted from the acid-catalyzed dehydration. The indoleninium intermediate 19 can react intennolecularly with 16 or 20 as shown in Scheme 6, or with other nucleophiles in the reaction mixture such as 17. Similarly, beside undergoing intramolecular cyclization, the indoleninium precursor to 20 can also react with 17, or with 19. Furthermore, each condensation can potentially produce a new indoleninium intermediate upon dehydration, which can still undergo further electrophilic additions. All of these reactions may account for the numerous products that were obtained.
9. 9. Illi, V.O. Synthesis, 1979, 136.
10. 10. Trost, B.M.; Arndt, H.C.; Strege, P.E.; Verboeven, T.R. Tetrahedron Lett., 1976, 3477.
11. 11. Saulnier, M.G.; Gribble, G.W. J. Org. Chem., 1982, 47, 757.
12. 12. Aristoff; P.A.; Johnson, P.D.; Harrison, A.W. J. Am. Chem. Soc., 1985, 107, 7967.
13. 13. Burla, M.C.; Camalli, M.; Cascarano, G.; Giacovazzo, C.; Polidori, G.; Spagna, R.; Viterbo, D. J. Appl. Crystallogr., 1989, 19, 3899.
14. 14. Cromer, D.T.; Waber, J.T. International Tables for X-Ray Crystallography, Kynoch Press, Birmingham, 1974, 4, (a) Table 2.2B, (b) Table 2.3.1
15. 15. teXsan: Crystal Structure Analysis Package, Molecular Structure Corporation, the Woodlands, TX, 1985 and 1992.