Cp2TiPh-coordinated cyano and ester groups as efficient ketyl radical acceptors in the reductive radical cyclization of γ- And δ-cyano ketones and δ-keto esters

Chemical Communications

Volumn , Issue 8, 1998, Pages 875-876

  Yamamoto, Yoshihiko ^a   Matsumi, Daisuke ^a   Itoh, Kenji ^a  

^a NAGOYA UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0002998515     PISSN: 13597345     EISSN: None     Source Type: Journal    
DOI: 10.1039/a800661j     Document Type: Article

References (11)

1. D. P. Curran, in Comprehensive Organic Synthesis, ed. B. M. Trost, Pergamon, Oxford, 1991, vol. 4, ch. 4.
2. 2TiPh.
3. 2TiPh(MeCN) (0.3 eV: UHF/PM3).
4. E. J. M. de Boer and J. H. Teuben, J. Organomet. Chem., 1978, 153, 53.
5. 2 was used to ensure completion of cyclization.
6. The structures and stereochemistry of cyclized products 2a-c, e-g were determined by comparison of their spectral features with those of reported compounds (ref. 7), and new compounds were characterized by the usual means.
7. T. Shono, N. Kise, T. Fujimoto, N. Tominaga and H. Morita, J. Org. Chem., 1992, 57, 7175.
8. iOH, the cyclization of Id afforded cyclized product 2 in 41% yield without formation of the simple reduced product cyano alcohol. This indicates that anionic species generated by the reduction of ketyl radicals are not involved in the present cyclization.
9. G. A. Molander and C. Kenny, J. Am. Chem. Soc., 1989, 111, 8236.
10. 2, where only a pinacol coupling product was obtained instead of a 5-exo cyclization product (E. J. Enholm and A. Trivellas, Tetrahedron Lett., 1989, 30, 1063.).
11. E. J. Corey and S. G. Pyne, Tetrahedron Lett., 1983, 24, 2821.