4700
M. Curini et al. / Tetrahedron Letters 47 (2006) 4697–4700
16H), 3.45–4.82 (m, 1H), 5.39 (s, 1H); 13C NMR
(50 MHz, CDCl3) d 199.2, 161.0, 108.4, 80.2, 36.0,
35.3, 28.2, 25.1, 23.8, 20.6; GC/MS: M+ = 194.
Acknowledgments
Financial support from MIUR National Project ‘Svilup-
po di processi sintetici ecocompatibili nella sintesi orga-
nica’, COFIN 2004 is gratefully acknowledged. F.E. also
wishes to thank Consorzio Cresci, Perugia, Italy.
Authors also wish to thank Paola Pisani and Maria
Grazia Lamagna for their helpful and friendly
collaboration.
3-(Benzyloxy)cyclohex-2-en-1-one (5): pale yellow oil;
1H NMR;8 C NMR;8 GC/MS: M+ = 202.
13
Synthesis of acyclic b-keto enol ethers. Typical procedure
A mixture of b-diketone (2.0 mmol) and alcohol
(2.0 mmol) was stirred well with Yb(OTf)3 (0.1 mmol)
at 50 ꢁC for 12 h. Following which NaOH 1 N (2 mL)
was added, the white precipitate filtered and the result-
ing solution extracted with Et2O (3 · 2 mL). Collected
organic phases were dried over anhydrous Na2SO4 and
the solvent evaporated to dryness to give the desired
product.
Supplementary data
Supplementary data associated with this article can be
1
References and notes
(3E)-4-Methoxypent-3-en-2-one (6): pale yellow oil; H
NMR;14 C NMR;14 GC/MS: M+ = 114.
13
1. (a) Marshall, D. R.; Roberts, T. R. J. Chem. Soc. 1971,
797–800; (b) House, H. O.; Rasmusson, G. H. J. Org.
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2. Zimmerman, H. E.; Wang, P. A. J. Am. Chem. Soc. 1993,
115, 2205–2216.
(3E)-4-Ethoxypent-3-en-2-one (7): pale yellow oil; 1H
NMR;8 C NMR;14 GC/MS: M+ = 128.
13
(3E)-4-Isopropoxypent-3-en-2-one (8): pale yellow oil;
1H NMR;15 C NMR;15 GC/MS: M+ = 142.
13
3. Mphahlele, M. J.; Modro, T. A. J. Org. Chem. 1995, 60,
8236–8240.
4. Nelson, P. H.; Nelson, J. T. Synthesis 1992, 1287–1291.
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1991, 47, 173–182.
6. Liu, H. J.; Tran, D. D. P. Nat. Prod. Lett. 1998, 11, 251–
253.
(3E)-4-(Cyclohexyloxy)pent-3-en-2-one (9): pale yellow
oil; 1H NMR (200 MHz, CDCl3) d 1.20–1.85 (m,
10H), 1.99 (s, 3H), 2.04 (s, 3H), 3.55–3.72 (m, 1H),
4.68 (s, 1H); 13C NMR (50 MHz, CDCl3) d 196.4,
161.2, 108.4, 80.2, 35.1, 25.0, 23.7, 23.4, 21.5; GC/MS:
M+ = 182.
7. Clerici, A.; Pastori, N.; Porta, O. Tetrahedron 2001, 57,
217–225, and reference cited herein.
8. Bhosale, R. S.; Bhosale, S. V.; Wang, T.; Zubaidha, P. K.
Tetrahedron Lett. 2004, 45, 7187–7188.
9. Murugan, R.; Kamakshi, R.; Reddy, B. S. R. Aust.
J. Chem. 2005, 58, 228–230.
10. Chandrasekhar, S.; Rao, Y. S.; Reddy, N. R. Synlett 2005,
9, 1471–1473.
11. Murugan, R.; Reddy, B. S. R. Ind. J. Chem. Sect. B. 2005,
44, 1512–1515.
(3E)-4-(Benzyloxy)pent-3-en-2-one (10): pale yellow oil;
1H NMR (200 MHz, CDCl3) d 2.05 (s, 3H), 2.08 (s, 3H),
4.75 (s, 2H), 5.24 (s, 1H), 7.26–7.49 (m, 5H); 13C NMR
(50 MHz, CDCl3) d 193.1, 165.2, 153.6, 143.5, 142.9,
142.7, 104.9, 86.7, 22.3, 18.1; GC/MS: M+ = 190.
(2E)-3-Methoxy-1-phenylbut-2-en-1-one (11): pale yel-
12. Kobayashi, S.; Sugiura, M.; Kitagawa, H.; Lam, W. L.
Chem. Rev. 2003, 6, 2227–2302.
1
13
low oil. H NMR;19 C NMR;19 GC/MS: M+ = 176.
13. Curini, M.; Epifano, F.; Genovese, S.; Marcotullio, M. C.;
Rosati, O. Org. Lett. 2005, 1331–1334, and references
cited herein.
(2E)-3-Ethoxy-1-phenylbut-2-en-1-one (12): pale yellow
1
13
oil. H NMR;19 C NMR;19 GC/MS: M+ = 190.
14. Kraus, M. E.; Sy, J. Org. Synth. 1989, 67, 202.
15. Shono, T.; Kashimura, S.; Sawamura, M.; Soejima, T.
J. Org. Chem. 1988, 53, 907–910.
16. Yogev, A.; Mazur, Y. J. Org. Chem. 1967, 32, 2162.
17. For the formation of lanthanide-b-diketonato complexes
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Chem. 2002, 32, 465–473.
18. After having recovered and recycled the catalyst by the
procedure described herein, the reaction to yield com-
pound 1 has been repeated three more times with the
following yields: 96%, 97%, 96%.
(2Z)-3-Methoxy-1,3-diphenylprop-2-en-1-one (13): pale
yellow oil. 1H NMR;19 C NMR;19 GC/MS: M+ = 238.
13
Recovery of the catalyst. Typical procedure
The precipitate filtered after work-up of the reaction was
suspended in H2O (2 mL), the mixture was acidified with
CF3SO3H and the resulting solution stored at 0 ꢁC for
24 h; the white precipitate formed was filtered, dried at
70 ꢁC for 5 h and used for further reactions.
19. Nishino, T. Synthesis 1980, 12, 1013–1015.