Phosphonate modification for a highly (Z)-selective synthesis of unsaturated esters by Horner-Wadsworth-Emmons olefination

European Journal of Organic Chemistry

Volumn , Issue 9, 2005, Pages 1790-1794

  Touchard, François P ^a  

^a Rhodia Recherches   (France)

Author keywords

Alkenes; Olefmation; Wittig reaction

Indexed keywords

EID: 18744374467     PISSN: 1434193X     EISSN: None     Source Type: Journal    
DOI: 10.1002/ejoc.200400769     Document Type: Article

References (17)

1. For a general review concerning the Wittig olefination reaction and modifications see: B. E. Maryanoff, A. B. Reitz, Chem. Rev. 1989, 89, 863-927.
2. W. C. Still, C. Gennari, Tetrahedron Lett. 1983, 24, 4405-4408.
3. K. Ando, Tetrahedron Lett. 1995, 36, 4105-4108.
4. Since the first publication of Ando (ref. 3) many phosphonate modifications have been reported a) K. Ando, J. Org. Chem. 1997, 62, 1934-1939;
5. b) K. Ando, J. Org. Chem. 1998, 63, 8411-8416;
6. c) K. Ando, J. Org. Chem. 1999, 64, 8406-8408;
7. d) K. Ando, T. Oishi, M. Hirama, H. Ohno, T. Ibuka, J. Org. Chem. 2000, 65, 4745-4749;
8. e) K. Kokin, J. Motoyoshiya, S. Hayashi, H. Aoyama, Synth. Commun. 1997, 27, 2387-2392;
9. f) K. Kokin, K. Iitake, Y. Takaguchi, H. Aoyama, S. Hayashi, J. Motoyoshiya, Phosphorus, Sulfur Silicon 1998, 133, 21-40.
10. For recent reviews, see: a) K. Ando, Yuki Gosei Kagaku Kyokaishi 2000, 55, 869-876;
11. b) J. Motoyoshiya, Trends Org. Chem. 1998, 7, 63-73.
12. The phosphonate based on 2,4-difluorophenol described by Motoyoshiya et al. (ref. 4e-4f) was the only one reported to date leading to selectivities over 92% at 0°C with various aldehydes.
13. F. P. Touchard, Tetrahedron Lett. 2004, 45, 5519-5523.
14. This purification could not be performed with the ketal as the phosphite remained adsorbed on alumina.
15. Ando has shown that NaI/DBU is an effective combination, especially with aliphatic aldehydes. In a preliminary screening, we have seen that TMG and DBU lead to the same results and that Nal/TMG also gives promising selectivities with benzaldehyde.
16. During this work, an article entitled "Excess sodium ions improve (Z)-selectivity in Horner-Wadsworth-Emmons ole-finations with the Ando phosphonate" was published: P. M. Pihko, T. M. Salo, Tetrahedron Lett. 2003, 44, 4361-4364.
17. B. E. Pape, M. F. Para, M. J. Zabik, J. Agric. Food Chem. 1970, 18, 490-493.