Her Carbene Complex: Unusually Efficient and General Benzannulation of Amino-Stabilized Alkenyl Fischer Carbene Complexes

Journal of Organic Chemistry

Volumn 63, Issue 22, 1998, Pages 7588-7589

  Barluenga, Jose ^a   Löpez, Luis A ^a   Martmez, Silvia ^a   Tomâs, Miguel ^a  

^a UNIVERSITY OF OVIEDO   (Spain)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001002889     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo981638k     Document Type: Article

References (25)

1. Recent reviews: (a) Wulff, W. D. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds; Pergamon: New York, 1991; Vol. 5, p 1065.
2. (b) Wulff, W. D. In Comprehensive Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: New York, 1995; Vol. 12, p 469.
3. Doyle, M. P. In Comprehensive Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: New York, 1995; Vol. 12, p 387.
4. Wulff, W. D. In Advances in Metal-Organic Chemistry; Liebeskind, L. S., Ed.; JAI Press: Greenwich, CT, 1989; Vol. 1. See also
5. (e) Harvey, D. F.; Sigano, D. M. Chem. Rev. 199G, 96, 271.
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8. (a) Dötz, K. H. Angew. Chem., Int. Ed. Engl. 1975,14, 644.
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10. Hoffmann, M.; Buchert, M.; Reissig, H.-U. Angew. Chem., Int. Ed. Engl. 1997, 36, 283.
11. (a) Recently, Dötz et al. have reported the intramolecular benzannulation of alkenyl(amino)carbene complexes with <20% yield: Dötz, K. H.; Lcese, T. Bull. Soc. Chim. Fr. 1997, 134, 503. Leading references for aryl amino carbene complexes
12. (b) Yamashita, A. Tetrahedron Lett. 1986, 27, 5915.
13. Dötz, K. H.; Erben, H. G.; Harms, K. J. Chem. Soc., Chem. Commun. 1989, 692.
14. Grotjahn, D. B.; Dötz, K. H. Synlett 1991, 381.
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16. (f) Parlier, A.; Rudier, M.; Rudier, H.; Goumont, R.; Daran, J. C.; Vaissermann, J. Organometallics 1995,14, 2760.
17. Wulff, W. D.; Gilbert, A. M.; Hsung, R. P.; Rahm, A. J. Org. Chem. 1995, 60, 4566.
18. The preparation and the benzannulation reaction of some electronpoor aryl Fischer carbene complexes have been advanced: Liptak, V. P.; Wulff, W. D. Abstracts of Papers, 214th National Meeting of the American Chemical Society, Las Vegas, NV, Sept 1997; American Chemical Society: Washington, DC, 1997; ORG 309.
19. Baldoli, C.; Del Buttero, P.; Licandro, E.; Maiorana, S.; Papagni, A.; Zanotti-Gerosa, A. Synlett 1993, 935.
20. 2 (30 mL) at 0 °C for 2 h to give, after quenching with methanol (20 mL) and chromatography on silica gel, the mesylate derivative 3. A solution of compound 3 (8 mmol) in diethyl ether (30 mL) was treated with DBU (12 mmol) and the resulting mixture stirred at room temperature overnight. Aqueous workup and Chromatographie purification on silica gel furnished the carbene complex 1 as a yellow solid in 72% overall yield. Experimental Procedure for the Benzannulation Reaction: To a solution of complex 1 (0.2 mmol) in THF (7 mL) was added an excess of the appropriate alkyne at room temperature. The mixture was heated (16 h for 5a-d,g, 48 h for 5e-f, and 6a-c) at 60 °C. The solvent was then removed, and the resulting residue was subjected to flash chromatography on silica gel using mixtures of hexane/ethyl acetate (5a-b,d-g and 6a,b) and hexane/dichloromethane (5c and 6c) as eluents.
21. 4JH-H for the aromatic hydrogens of 5 was 2-3 Hz. The regiochemistry of 6c was determined by 2D NOESY experiments.
22. For the preparation of protected hydroquinone chromiumftricarbonyl) complexes from alkenyl(alkoxy)carbene complexes, see: Chamberlin, S.; Wulff, W. D.; Bax, B. Tetrahedron 1993,49, 5531.
23. Even in the case of Fischer alkoxycarbene complexes, the presence of carbonyl groups conjugated with the alkyne is a major limitation for the benzannulation reaction. Specifically, alkenyl(alkoxy)carbene derivatives lead to phenol derivatives in <22% yield; see, for instance: Wulff, W. D.; Chang, K.-S.; Tang, P.-C. J. Org. Chem. 1984, 49, 2293.
24. Compounds of type 5e seem to be attractive as ligands in transitionmetal catalysis after appropriate derivatization of both ester functions. For recent preparation and coordination chemistry of related ligands, see: (a) Fharni, C. J.; Pfalz, A. Helv. Chim. Acta 1998, 81, 491.
25. (b) Fharni, C. J.; Pfalz, A.; Neuburger, M.; Zehnder, M. Helv. Chim. Acta 1998, 81, 507.