TEMPO-Catalyzed Aerobic Oxidation of Alcohols to Aldehydes and Ketones in Ionic Liquid [bmim][PF6]

Organic Letters

Volumn 4, Issue 9, 2002, Pages 1507-1509

  Ansari, Imtiaz A ^a   Gree, Rene ^a  

^a UNIV RENNES   (France)

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE;

EID: 0000503616     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol025721c     Document Type: Article

References (29)

1. For recent reviews, see: (a) Welton, T. Chem. Rev. 1999, 99, 2071.
2. (b) Wasserscheid, P.; Keim, W. Angew. Chem., Int. Ed. 2000, 39, 3772.
3. (c) Sheldon, R. A. Chem. Commun. 2001, 2399 and references therein.
4. For recent examples, see: (a) Miyata, A.; Murakami, M. Irie, R.; Katsuki, T. Tetrahedron Lett. 2001, 42, 7067.
5. (b) Lee, M.; Chang, S. Tetrahedron Lett. 2000, 41, 7507.
6. (c) Kakiuchi, N.; Maeda, Y.; Nishimura, T.; Uemura, S. J. Org. Chem. 2001, 66, 6620.
7. (d) Steinhoff, B. A.; Fix, S. R.; Stahl, S. S. J. Am. Chem. Soc. 2002, 124, 766 and references therein.
8. Semmelhack, F. M.; Schmidt, C. R.; Cortés, D. A.; Chou, C. S. J. Am. Chem. Soc. 1984, 106, 3374.
9. (a) de Nooy, A. E. J.; Besemer, A. C.; van Bekkum, H. Synthesis 1996, 1153.
10. (b) de Mico, A.; Margarita, R.; Parlanti, L.; Vescovi, A.; Piancatelli, G. J. Org. Chem. 1997, 62, 6974.
11. (c) Anelli, P. L.; Biffi, C.; Montanari, F.; Quici, S. J. Org. Chem. 1987, 52, 2559.
12. (d) Bolm, C.; Magnus, A. S.; Hilderbrand, J. P. Org. Lett. 2000, 2, 1173.
13. (e) De Luca, L.; Giacomelli, G.; Porcheddu, A. Org. Lett. 2001, 3, 3041.
14. Howarth, J. Tetrahedron Lett. 2000, 41, 6627.
15. Ley, S. V.; Ramarao, C. Smith, M. D. Chem. Commun. 2001, 2278.
16. Owens, G S.; Abu-Omar, M. M. Chem. Commun. 2000, 1165.
17. Song, C. E.; Roh, E. J. Chem. Commun. 2000, 837.
18. Singer, R. D.; Scammells, P. J. Tetrahedron Lett. 2001, 42, 6831.
19. Le Boulaire, V.; Gree, R. Chem. Commun. 2000, 2195.
20. 6] under our reaction conditions (see representative experimental procedure).
21. For the synthesis of 1, see: Fuller, J.; Carlin, R. T.; De Long, H. C.; Haworth, D. Chem. Commun. 1994, 299.
22. 2 (1 atm.). The reaction mixture was extracted with diethyl ether (3 x 8 mL). The ether layer was concentrated in vacuo. Filtration of the extract over short silica gel pad afforded benzaldehyde (76.5 mg, yield 72%).
23. All of the isolated compounds (purity >98% checked by NMR and GC) have spectral data in agreement with the literature. Furthermore, in all cases except entries 8, 10, and 15 where the compounds were not readily available, all carbonyl derivatives have shown identity (GC, NMR) with authentic samples.
24. Cecchetto, A.; Fontana, F., Minisci, F.; Recupero, F. Tetrahedron Lett. 2001, 42, 6651.
25. 13C NMR spectrum between 50 and 250 ppm there are only three peaks at 123.2, 124.5, and 137.2 ppm corresponding to the imidazolium carbons.
26. After the extraction, the ionic solvents was washed with water (10 mL) and dried at 70°C for 7 h under high vacuum before next run.
27. GC analysis of the reaction mixture at different intervals showed a slow degradation of the catalyst (TEMPO).
28. The catalyst being extracted along with the product, after three extractions the ionic liquid was left with no trace of catalyst.
29. 2 atmosphere (Table 1).