Reactive Ketenes through a Carbonate/Amine Shuttle Deprotonation Strategy: Catalytic, Enantioselective α-Bromination of Acid Chlorides

Organic Letters

Volumn 3, Issue 13, 2001, Pages 2049-2051

  Hafez, Ahmed M ^a   Taggi, Andrew E ^a   Wack, Harald ^a   Esterbrook, Julie ^a   Lectka, Thomas ^a  

^a JOHNS HOPKINS UNIVERSITY   (United States)

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EID: 0000712093     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0160147     Document Type: Article

References (20)

1. Tidwell, T. T. Ketenes; John Wiley & Sons: New York, 1995.
2. (a) Palomo, C.; Aizpurua, J. M.; Ganboa, I.; Oiarbide, M. Eur. J. Org. Chem. 1999, 3223-3235.
3. (b) Lynch, J. E.; Riseman, S. M.; Laswell, W. L.; Tschaen, D. M.; Volante, R. P.; Smith, G. B.; Shinkai, I. J. Org. Chem. 1989, 54, 3792-3796.
4. Taggi, A. E.; Hafez, A. M.; Wack, H.; Young, B.; Drury, W. J., III; Lectka, T. J. Am. Chem. Soc. 2000, 122, 7831-7832.
5. We published a preliminary report focusing primarily on α-chlorinations: (a) Wack, H.; Taggi, A. E.; Hafez, A. M.; Drury, W. J., III; Lectka, T. J. Am. Chem. Soc. 2001, 123, 1531-1532. For other representative asymmetric α-halogenation reactions, see: (catalytic)
6. (b) Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. 2000, 39, 4359-4362. (auxiliary-based)
7. (c) Enders, D.; Klein, D. Synlett 1999, 719-720.
8. (d) Enders, D.; Potthoff, M.; Raabe, G.; Runsink, J. Angew. Chem., Int. Ed. 1997, 36, 2362-2364.
9. (e) Oppolzer, W.; Dudfield, P. Tetrahedron Lett. 1985, 26, 5037-5040.
10. (f) Evans has developed an auxiliary-based route to α-chloroimides: Evans, D. A.; Ellman, J. A.; Dorow, R. L. Tetrahedron Lett. 1987, 28, 1123-1126.
11. 3 is available from Aldrich and several other companies.
12. (a) Nelson, A. Angew. Chem., Int. Ed. 1999, 38, 1583-1585. For other dual uses of amine/carbonate base systems, see:
13. (b) Tanabe, Y.; Yamamoto, H.; Yoshida, Y.; Miyawaki, T.; Utsumi, N. Bull. Chem. Soc. Jpn. 1995, 68, 297-300.
14. (c) Sasson, Y.; Bilman, N. J. Chem. Soc., Perkin Trans. 2 1989, 2029-2033.
15. This flask will soon be commercially available from ChemGlass.
16. (a) Bright, R.; Freeman, S.; Hayes, D.; Smith, G.; Tapolczay, D.; Coote, S. J. Synth. Comm. 1996, 26, 4195-4209.
17. (b) Khan, G, R.; Leahy, D. E.; Katrizky, A. R. J. Org. Chem. 1984, 49, 4784-4786.
18. (a) Hafez, A. M.; Taggi, A. E.; Wack, H. W.; Drury, W. J., III; Lectka, T. Org. Lett. 2000, 2, 3963-3965.
19. (b) Schwesinger, R.; Willaredt, J.; Schempler, H.; Keller, M.; Schmitt, D.; Fritz, H. Chem. Ber. 1994, 127, 2435-2454.
20. Product yields are based on the most expensive component in the reaction, usually the brominating reagent. See the Supporting Information for details and a general procedure.