Synthesis of β,γ-Unsaturated Ketones via Cerium-Mediated Addition of Organolithiums to Silylated Enaminones

Journal of Organic Chemistry

Volumn 63, Issue 11, 1998, Pages 3745-3747

  Dalpozzo, Renato ^a   De Nino, Antonio ^a   Bartoli, Giuseppe ^b   Bosco, Marcella ^b   Sambri, Letizia ^b   Marcantoni, Enrico ^c  

^a UNIVERSITY OF CALABRIA   (Italy)

^b UNIVERSITY OF BOLOGNA   (Italy)

^c Universita   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001427380     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo971520o     Document Type: Article

References (20)

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2. Pollack, R. M.; Bounds, P. L.; Bevis C. L. In The Chemistry of Enones Part 1; Patai, S., and Zappoport, Z., Eds.; John Wiley & Sons: New York, 1989; p 599.
3. Zaidlewicz, M. Synthesis 1988, 701.
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11. The water molecule found in "dry" cerium(III) chloride seems to have no effect on the reagent, since the whole organolithium regent should be destroyed by this adventitious water, cf. Evans, W. J.; Feldman, J. D.; Ziller J. W. J. Am. Chem. Soc. 1996, 118, 4581.
12. Bartoli, G.; Marcantoni, E.; Petrini, M.; Sambri, L. Chem. Eur J. 1996, 2, 913.
13. 1H NMR relevant peaks δ 0.34 (s, 6H), 1.72 and 1.22 (s, 9H), 2.00 and 2.03 (s, 2H), 2.13 and 2.14 (s, 3H), 6.04 and 6.06 (s, 1H). Chromatography of the mixture caused the imino function to be hydrolyzed (82% yield of recovered ketone). The same product was obtained in comparable yields (89%, E/Z ratio 1.8/1) by quenching of the reaction with 10% HCl solution.
14. The crude product 3a allowed to stand on silica gel overnight was almost quantitatively converted into 5a.
15. Rupe, H. and Gassman, A. Helv. Chim. Acta 1936, 19, 569.
16. A number of syntheses have been reported leading to racemic turmerone; see among others: (a) Crawford, R. J.; Erman, W. F.; Broaddus C. D. J. Am. Chem. Soc. 1972, 94, 4298.
17. (b) Snowden, R. L.; Linder, S. M.; Muller, B. L.; Schulte-Elte, K. H. Helv. Chim. Acta 1987, 70, 1858.
18. (c) Sakai, T.; Miyata, K.; Utaka, M.; Takeda, A. Tetrahedron Lett. 1987, 3817.
19. (d) Hayakawa, S.; Michiue, T.; Okamoto, M.; Hatakeiama, S.; Ohta, S. Heterocycles 1988, 27, 457.
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