Rhodium(I)-catalyzed cyclization reaction of o-alkynyl phenols and anilines. Domino approach to 2,3-disubstituted benzofurans and indoles

Organic Letters

Volumn 11, Issue 6, 2009, Pages 1329-1331

  Isono, Naohiro ^a   Lautens, Mark ^a  

^a UNIVERSITY OF TORONTO   (Canada)

Author keywords

[No Author keywords available]

Indexed keywords

ALKYNE; ANILINE DERIVATIVE; BENZOFURAN DERIVATIVE; INDOLE DERIVATIVE; PHENOL DERIVATIVE; RHODIUM;

ARTICLE; CATALYSIS; CHEMICAL STRUCTURE; CHEMISTRY; COMBINATORIAL CHEMISTRY; CYCLIZATION; STEREOISOMERISM; SYNTHESIS;

ALKYNES; ANILINE COMPOUNDS; BENZOFURANS; CATALYSIS; COMBINATORIAL CHEMISTRY TECHNIQUES; CYCLIZATION; INDOLES; MOLECULAR STRUCTURE; PHENOLS; RHODIUM; STEREOISOMERISM;

EID: 64049106171     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol9001174     Document Type: Article

References (22)

1. Benzofuran: Keay, B. A.; Dibble, P. W. In ComprehensiVe Heterocyclic Chemistry II; Katritzky, A. R., Rees, C. W., Scriven, E. F. V., Eds.; Pergamon Press: Oxford, UK, 1996; Vol. 2, p 395. Indole: Gribble, G. W.; In Comprehensive Heterocyclic Chemistry II; Katritzky, A. R., Rees, C. W., Scriven, E. F. V., Eds.; Pergamon Press: Oxford, UK, 1996; Vol. 2, p 207.
2. For reviews, see: Zeni, G.; Larock, R. C. Chem. Rev. 2004, 104, 2285, and references therein.
3. Leading references: (a) Kondo, Y.; Shiga, F.; Murata, N.; Sakamoto, T.; Yamanaka, H. Tetrahedron 1994, 50, 11803.
4. (b) Arcadi, A.; Cacchi, S.; Del Rosario, M.; Fabrizi, G.; Marinelli, F. J. Org. Chem. 1996, 61, 9280.
5. (c) Nakamura, I.; Mizushima, Y.; Yamamoto, Y. J. Am. Chem. Soc. 2005, 127, 15022.
6. (d) Fürstner, A.; Davies, P. W. J. Am. Chem. Soc. 2005, 127, 15024.
7. (e) Nakamura, M.; Ilies, L.; Otsubo, S.; Nakamura, E. Org. Lett. 2006, 8, 2803, and references therein.
8. For a recent example of benzofuran synthesis via dealkylationcyclization by a rhodium catalyst: (a) Oppenheimer, J.; Johnson, W. L.; Tracey, M. R.; Hsung, R. P.; Yao, P.-Y.; Liu, R.; Zhao, K. Org. Lett. 2007, 9, 2361. Intramolecular hydroamination:
9. (b) Liu, Z.; Hartwig, J. F. J. Am. Chem. Soc. 2008, 130, 1570. Amino-Claisen rearrangement of N -propargyl anilines:
10. (c) Saito, A.; Kanno, A.; Hanzawa, Y. Angew. Chem., Int. Ed. 2007, 46, 3931.
11. Trost, B. M.; McClory, A. Angew. Chem. Int. Ed. 2007, 46, 2074.
12. For reviews on rhodium-catalyzed 1, 4-addition, see: (a) Fagnou, K.; Lautens, M. Chem. Rev. 2003, 103, 169.
13. (b) Hayashi, T.; Yamasaki, K. Chem. Rev. 2003, 103, 2829.
14. (c) Miura, T.; Murakami, M. Chem. Commun. 2007, 217.
15. For a recent example of a rhodium-catalyzed cascade reaction consisting of ring expansion/1, 4-addition: Matsuda, T.; Shigeno, M.; Murakami, M. J. Am. Chem. Soc. 2007, 129, 12086.
16. Lu reported that LiBr inhibited β-hydride elimination in a palladiumcatalyzed aminopalladation, addition reaction (ref 9a). In our case, there was not an obvious effect with LiBr in the reaction.
17. For a recent example of tandem intramolecular cyclization of alkynylanilines and conjugate addition, see: (a) Pd: Shen, Z.; Lu, X Tetrahedron 2006, 62, 10896.
18. (b) Au: Alfonsi, M.; Arcadi, A.; Aschi, M.; Bianchi, G.; Marinelli, F. J. Org. Chem. 2005, 70, 2265.
19. Heating a dioxane solution of 1a and ethyl vinyl ketone at 90 °C in the absence of the rhodium catalyst gave no 1, 4-adduct product and recovered 1a (100%).
20. A control experiment was conducted using the rhodium catalyst in the presence of preformed benzofuran 2a and acrylonitrile. No addition product was obtained, and the starting material was recovered in high yield.
21. This reaction was carried out without water at 90 °C in 6 h. 11 was obtained in 11%, and 10 was recovered (49%).
22. Following acceptance of this manuscript a recent paper appeared on related reactions using Pd (II) catalysts: Martínez, C; Álverez, R. Aurrecoechea, J. M. Org. Lett. 2009, 11, 1083-1086.