Uncatalyzed Friedel-Crafts alkylation of aromatic compounds through reactive benzyl cations generated from N-sulfamoylcarbamates

Organic Letters

Volumn 5, Issue 2, 2003, Pages 193-196

  Sefkow, Michael ^a   Buchs, Jens ^a  

^a UNIVERSITY OF POTSDAM   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

AROMATIC COMPOUND; BENZYL DERIVATIVE; CARBAMIC ACID DERIVATIVE; CATION;

ARTICLE; CATALYSIS; CHEMICAL REACTION; FRIEDEL CRAFTS REACTION; THERMODYNAMICS;

EID: 0141518167     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0272489     Document Type: Article

References (22)

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5. Darbeau, R. W.; White, E. H. J. Org. Chem. 1997, 62, 8091-8092.
6. Additionally, the employed N-benzyl-N-nitrosoamides are thermolabile, sensitive to hydrolysis, and highly carcinogenic, thus preventing a general use of these compounds.
7. LONZA-COR Publication Chlorosulfonyl Isocyanate, 2nd ed.; 1980.
8. (a) Burke, P. O.; McDermott, S. D.; Hannigan, T. W.; Spillane, W. J. J. Chem. Soc., Perkin Trans. 1 1984, 1851-1854.
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10. Buchs, J. Ph.D. Thesis, Universität Potsdam, Potsdam, Germany, 1999.
11. For similar syntheses using CSI, see: (a) Dewynter, G.; Montero, J.-L. C. R. Acad. Sci., Ser. II 1992, 315, 1675-1682. (b) Muller, G. W.; DuBois, G. E. J. Org. Chem. 1989, 54, 4471-4473. Since CSI is known to be the most reactive isocyanate, this reagent must be handled with care. On the other hand, the sulfamoylcarbamates 1-4 exhibit low cytotoxicity (unpublished results).
12. For similar syntheses using CSI, see: (a) Dewynter, G.; Montero, J.-L. C. R. Acad. Sci., Ser. II 1992, 315, 1675-1682. (b) Muller, G. W.; DuBois, G. E. J. Org. Chem. 1989, 54, 4471-4473. Since CSI is known to be the most reactive isocyanate, this reagent must be handled with care. On the other hand, the sulfamoylcarbamates 1-4 exhibit low cytotoxicity (unpublished results).
13. This is particularly interesting in cases where monoalkylated products are difficult to obtain by standard Friedel-Crafts alkylation. See: Tsuchikawa, H.; Iwamoto, Y. (Nisshin Oil Mills, Ltd.) JP 11 228,459, 1999; Chem. Abstr. 1999, 131, 171853h.
14. Structures of products obtained by the interception of benzyl cations with the carbonyl or nitrile group were not determined. For some recent studies on this topic, see: Darbeau, R. W.; White, E. H.; Nunez, N.; Coit, B.; Daigle M. J. Org. Chem. 2000, 65, 1115-1120. Song, F.; Darbeau, R. W.; White, E. H. J. Org. Chem. 2000, 65, 1825-1829.
15. Structures of products obtained by the interception of benzyl cations with the carbonyl or nitrile group were not determined. For some recent studies on this topic, see: Darbeau, R. W.; White, E. H.; Nunez, N.; Coit, B.; Daigle M. J. Org. Chem. 2000, 65, 1115-1120. Song, F.; Darbeau, R. W.; White, E. H. J. Org. Chem. 2000, 65, 1825-1829.
16. 2: Burke, J. R.; Witmer, M. R.; Zusi, F. C.; Gregor, K. R.; Davern, L. B.; Padmanabha, R.; Swann, R. T.; Smith, D.; Tredup, J. A.; Micanovic, R.; Manly, S. P.; Villafranca, J. J.; Tramposch, K. M. J. Biol. Chem. 1999, 274, 18864-18871.
17. 2O, respectively, act as neutral molecules. See ref 1.
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19. (b) Houk, K. N.; Strozier, R. W.; Hall, J. A. Tetrahedron Lett. 1974, 897-900.
20. 2). The latter is probably produced by the oxidation of the benzyl cation. The molecular compositions of these fragments were established by high-resolution mass spectrometry. Although pathway A seems more likely, the preliminary mass spectrometric studies indicate that pathway B cannot be ruled out.
21. For example, cyclopenene, derived from elimination from cyclopentyl sulfamoylcarbamate, was easily identified by its odor and, subsequently, by proton NMR. However, starting materials without β-protons such as neopentyl sulfamoylcarbamate yield three major products whose structures are currently unknown. These products are crystalline compounds, and efforts are underway to obtain suitable crystals for X-ray crystallography.
22. Mayr, H.; Patz, M. Angew. Chem. 1994, 106, 990-1010.