Claisen-type condensation of vinylogous acyl triflates

Organic Letters

Volumn 8, Issue 1, 2006, Pages 175-177

  Kamijo, Shin ^a   Dudley, Gregory B ^a  

^a FLORIDA STATE UNIVERSITY   (United States)

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EID: 30944445644     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0527781     Document Type: Article

References (16)

1. For reviews on the Claisen condensation, see: (a) Davis, B. R.; Garratt, P. J. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon: Oxford, 1991; Vol. 2, pp 795-863.
2. (b) Hauser, C. R.; Hudson, D. E. Org. React. 1942, 1, 266.
3. (c) Hauser, C. R.; Swamer, F. W.; Adams, J. T. Org. React. 1954, 8, 59.
4. For a review on the Dieckman condensation, see: (d) Schaefer, J. P.; Bloomfield, J. J. Org. React. 1967, 15, 1.
5. (a) Kamijo, S.; Dudley, G. B. J. Am. Chem. Soc. 2005, 127, 5028.
6. (a) Eschenmoser, A.; Felix, D.; Ohloff, G. Helv. Chim. Acta 1967, 50, 708.
7. (b) Felix, D.; Shreiber, J.; Ohloff, G.; Eschenmoser, A. Helv. Chim. Acta 1971, 54, 2896.
8. (c) Tanabe, M.; Crowe, D. F.; Dehn, R. L. Tetrahedron Lett. 1967, 3943.
9. (d) Tanabe, M.; Crowe, D. F.; Dehn, R. L.; Detre, G. Tetrahedron Lett. 1967, 3739.
10. (a) Grob, C. A.; Schiess, P. W. Angew. Chem., Int. Ed. Engl. 1967, 6, 1.
11. (b) Grob, C. A. Angew. Chem., Int. Ed. Engl. 1969, 8, 535.
12. (c) Wharton, P. S.; Hiegel, G. A. J. Org. Chem. 1965, 30, 3254.
13. (d) Weyerstahl, P.; Marschall, H. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon: Oxford, 1991; Vol. 6, pp 1041-1070.
14. 3. See Supporting Information for details.
15. + = 261.1); however, the yield was quite low and we could not isolate the desired product in acceptable purity. In the latter case, the reaction resulted in decomposition of triflate 1a, and a significant amount of ethyl isobutyrate was recovered.
16. An alternative pathway, enolization of 1 and fragmentation to provide a ketene intermediate, is inconsistent with a deuterium-labeling experiment. See the Supporting Information for details.