(E)-Methyl 2,4-Pentadienoate

[1515-75-9]  · C6H8O2  · (E)-Methyl 2,4-Pentadienoate  · (MW 112.14)

(electron-poor diene capable of cycloaddition reactions with activated dienophiles to form carbocyclic1 and heterocyclic2 compounds; metal-promoted [6 + 4] cycloadditions3 and metal-promoted chain extensions4)

Physical Data: bp 55-57 °C/14 mmHg.

Solubility: sol most organic solvents.

Form Supplied in: colorless liquid.

Analysis of Reagent Purity: NMR.

Preparative Methods: Wittig alkenation of Acrolein with (Methoxycarbonylmethylene)triphenylphosphorane;5 reaction of Malonic Acid with acrolein, followed by esterification.6

Purification: distillation.

Handling, Storage, and Precautions: polymerizes easily.

Diels-Alder Reactions.

As an electron-poor diene, the cycloaddition reactions of (E)-methyl 2,4-pentadienoate are optimal when combined with electron-rich dienophiles such as enamines (eq 1).1 When electron-deficient dienophiles such as benzyljuglone,7 or relatively nonpolarized dienophiles are employed (eq 2),8 more forcing conditions are needed.

Heterocycle Synthesis.

Nitroso compounds can react with the dienoate to afford 3,6-dihydro-1,2-oxazines (eq 3).2 The 3,4-double bond can act as a 2p component in reactions with diphenylnitrilimine (eq 4).9

Metal-Promoted Reactions.

The diene is a useful acceptor in the Heck reaction (eq 5).4 It should be noted that the metal acts in a catalytic fashion in this reaction. When other reactants are not included in the reaction mixture, dimerization and further oligomerization is observed.10-12 Other metal-promoted reactions can induce cycloaddition processes. In a noncatalytic process, complexation of thiepin dioxide with chromium tricarbonyl brings about [6 + 4] cycloaddition (eq 6).3

1. Berchtold, G. A.; Ciabattoni, J.; Tunick, A. A. JOC 1965, 30, 3679.
2. Desai, M. C.; Doty, J. L.; Stephens, L. M.; Brighty, K. E. TL 1993, 34, 961.
3. Rigby, J. H.; Ateeq, H. S.; Charles, N. R.; Cuisiat, S. V.; Ferguson, M. D.; Henshilwood, J. A.; Krueger, A. C.; Ogbu, C. O.; Short, K. M.; Heeg, M. J. JACS 1993, 115, 1382.
4. Fischetti, W.; Mak, K. T.; Stakem, F. G.; Kim, J.-I.; Rheingold, A. L.; Heck, R. F. JOC 1983, 48, 948.
5. Cardellach, J.; Estopa, C.; Font, J.; Moreno-Manas, M.; Ortuno, R. M.; Sanchez-Ferrando, F.; Valle, S.; Vilamajo, L. T 1982, 38, 2377.
6. Doebner, O. CB 1902, 35, 1136.
7. Rougny, A.; Sebbata, A.; Fillion, H. BSB 1987, 96, 481.
8. Batty, D.; Langlois, Y. TL 1993, 34, 457.
9. Fliege, W.; Huisgen, R.; Kolbeck, W.; Weberndorfer, V. CB 1983, 116, 3438.
10. Tenaglia, A.; Brun, P.; Waegell, B. TL 1985, 26, 3571.
11. Buch, H. M.; Schroth, G.; Mynott, R.; Binger, P. JOM 1983, 247, C63.
12. Denis, P.; Croizy, J. F.; Mortreux, A.; Petit, F. J. Mol. Catal. 1991, 68, 159.

Richard T. Taylor

Miami University, Oxford, OH, USA

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