Metal-catalyzed cotrimerization of arynes and alkenes

Organic Letters

Volumn 8, Issue 15, 2006, Pages 3347-3350

  Quintana, Iago ^a   Boersma, Arnold J ^a,b   Peña, Diego ^a   Pérez, Dolores ^a   Guitián, Enrique ^a  

^a UNIVERSITY OF SANTIAGO DE COMPOSTELA   (Spain)

^b UNIVERSITY OF GRONINGEN   (Netherlands)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 33746894123     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0611954     Document Type: Article

References (32)

1. For reviews of aryne reactivity, see: (a) Hoffmann, R. W. Dehydrobenzene and Cycloalkynes; Academic Press: New York, 1967.
2. (b) Pellissier, H.; Santelli, M. Tetrahedron 2003, 59, 701.
3. For a recent review of palladium-catalyzed cycloaddition reactions of arynes, see: Guitián, E.; Pérez, D.; Peña, D. In Topics in Organometallic Chemistry; Tsuji, J., Ed.; Springer-Verlag: Weinheim, 2005; Vol. 14, pp 109-146.
4. Peña, D.; Escudero, S.; Pérez, D.; Guitián, E.; Castedo, L. Angew. Chem., Int. Ed. 1998, 37, 2659.
5. (a) Peña, D.; Pérez, D.; Guitián, E.; Castedo, L. J. Am. Chem. Soc. 1999, 121, 5827.
6. (b) Peña, D.; Pérez, D.; Guitián, E.; Castedo, L. J. Org. Chem. 2000, 65, 6944.
7. (c) Yoshikawa, E.; Radhakrishnan, K. V.; Yamamoto, Y. J. Am. Chem. Soc. 2000, 122, 7280.
8. (a) Peña, D.; Pérez, D.; Guitián, E.; Castedo, L. Eur. J. Org. Chem. 2003, 1238.
9. (b) Sato, Y.; Tamura, T.; Mori, M. Angew. Chem., Int. Ed. 2004, 43, 2436.
10. (c) Hsieh, J.-C.; Cheng, C.-H. Chem. Commun. 2005, 2459.
11. (a) Yoshikawa, E.; Yamamoto, Y. Angew. Chem., Int. Ed. 2000, 39, 173.
12. (b) Hsieh, J.-C.; Rayabarapu, D. K.; Cheng, C.-H. Chem. Commun. 2004, 532.
13. (c) Chatani, N.; Kamitani, A.; Oshita, M.; Fukumoto, Y.; Murai, S. J. Am. Chem. Soc. 2001, 123, 12686.
14. For recent examples of palladium-catalyzed reactions involving arynes besides cycloadditions, see: (a) Yoshida, H.; Tanino, K.; Ohshita, J.; Kunai, A. Angew. Chem., Int. Ed. 2004, 43, 5052.
15. (b) Liu, Z.; Zhang, X.; Larock, R. C. J. Am. Chem. Soc. 2005, 127, 15716.
16. (c) Jayanth, T.-T.; Cheng, C.-H. Chem. Commun. 2006, 894.
17. Jayanth, T.-T.; Jeganmohan, M.; Cheng, C.-H. J. Org. Chem. 2004, 69, 8445. Strained bicyclic alkenes are privileged substrates in palladium-catalyzed reactions because the intrinsic strain of these olefins favors their coordination to the metal.
18. An excess of the acrylate (3 equiv) was necessary to avoid the formation of triphenylene as the major product.
19. In the absence of palladium catalyst, none of the cotrimerization products were detected.
20. Under these conditions, the major reaction products resulted from the cyclotrimerization of benzyne and the [2+2] cycloaddition of benzyne to the alkene.
21. We found that (Z)-olefins are poor reaction partners in this cotrimerization. The formation of trans-3e from (Z)-2e is due to the partial Z/E isomerization of the olefin in the reaction mixture.
22. Geminally disubstituted olefins such as methyl methacrylate or dimethyl itaconate afforded yields below 30% of the corresponding products.
23. 3 as a ligand: a, 73% (4: 69:27); b, 78% (13:67:20).
24. Sambaiah, T.; Li, L.-P.; Huang, D.-J.; Lin, C.-H.; Rayabarapu, D. K.; Cheng, C.-H. J. Org. Chem. 1999, 64, 3663.
25. Alternatively, compound 3 could be produced via [4+2] cycloaddition of metallacycle 8 and the alkene, followed by reductive elimination of the metal. However, this pathway is unlikely because it initially requires the loss of the aromaticity of compound 8.
26. 2 was replaced by a methyl group (2f, entry 11, Table 1), only (E)-4f was obtained.
27. The predominant formation of metallacycle 11 is feasible, considering the excess of alkene present in the reaction mixture (3 equiv) compared to the maximum amount of benzyne-metal complex possible at any stage in the reaction (10 mol %). Metallacycles related to 11 have been isolated by reaction of electron-deficient alkenes with aryne-nickel complexes. See: Bennett, M. A.; Wenger, E. Chem. Ber. 1997, 130, 1029.
28. (a) Satoh, T.; Jones, W. D. Orgonometallics 2001, 20, 2916.
29. (b) Campo, M. A.; Larock, R. C. J. Am. Chem. Soc. 2002, 124, 14326.
30. (c) Masselot, D.; Charmant, J. P. H.; Gallagher, T. J. Am. Chem. Soc. 2006, 128, 694.
31. This alternative has been proposed by Yamamoto and co-workers for some Pd-catalyzed cyclizations of triflate 1 with alkynes (see ref 4c).
32. See Supporting Information for details.