Dimethyl Maleate

[624-48-6]  · C6H8O4  · Dimethyl Maleate  · (MW 144.14)

(useful as a dienophile; dipolarophile; Michael acceptor; radical acceptor)

Physical Data: bp 204-205 °C; d 1.152 g cm-3.

Solubility: sol most ethers and methanol.

Form Supplied in: colorless liquid; <=4% impurity of dimethyl fumarate.

Purification: distilled under reduced pressure.

Handling, Storage, and Precautions: toxic, irritant. Store in a brown bottle; avoid exposure to light.

Cycloadditions.

Dimethyl maleate is a doubly activated dienophile which reacts stereospecifically with a variety of dienes (see also Dimethyl Fumarate). Dimethyl maleate has been utilized in examining the stereoselectivity in the Diels-Alder reaction of substituted o-quinodimethanes (eq 1).1 The [4 + 2] cycloaddition between dimethyl maleate and a 1-amino-2-azadiene produces a dihydropyridine (eq 2).2 Dimethyl maleate is an excellent dipolarophile which may be used to probe the concertedness of a cycloaddition process. However, caution needs to be exercised in drawing conclusions regarding the concertedness of a reaction based upon the stereoselectivity since maleate has been observed to isomerize quantitatively to fumarate by basic catalysis prior to cycloaddition.3 The [3 + 2] cycloaddition of a variety of dipoles including trimethylenemethane (eq 3),4 azomethine ylide (eq 4),5 and nitrone (eq 5)6 proceed endo stereoselectively with retention of alkene geometry.

The photochemical7 and thermal8 cycloadditions of dimethyl maleate to alkenes have been examined. Thermal reactions require the use of electron-rich alkenes such as ketene dithioacetals or enamines (eq 6). As expected, the alkene geometry is not retained in either thermal or photochemical [2 + 2] cycloadditions of dimethyl maleate. The photochemical addition of dimethyl maleate proceeds in low chemical yield with poor stereoselectivity.

Miscellaneous.

Higher homologs of carbohydrates have been prepared through Tri-n-butylstannane-Azobisisobutyronitrile induced radical addition to dimethyl maleate (eq 7) (see also N-Phenylmaleimide and Dimethyl Fumarate).9 Other electron-deficient alkenes which have been utilized as radical acceptors include Acrylonitrile, Methyl Acrylate, Methyl Vinyl Ketone, and N-ethylmaleimide.

A useful phosphonate for the preparation of a variety of alkylidenesuccinates by an Emmons-Wadsworth-Horner reaction is prepared by refluxing a mixture of Trimethyl Phosphite and dimethyl maleate in phenol (eq 8).10

Related Reagents.

Dimethyl Fumarate.


1. Durst, T.; Kozma, E. C.; Charlton, J. L. JOC 1985, 50, 4829. (b) Charlton, J. L.; Alauddin, M. M.; Penner, G. H. CJC 1986, 64, 793. (c) Ito, Y.; Nakatsuka, M.; Saegusa, T. JACS 1982, 104, 7609.
2. Demoulin, A.; Gorissen, H.; Hesbain-Frisque, A-M.; Ghosez, L. JACS 1975, 97, 4409.
3. Tian, W-S.; Livinghouse, T. CC 1989, 819.
4. Ejiri, S.; Yamago, S.; Nakamura, E. JACS 1992, 114, 8707.
5. Williams, R. M.; Zhai, W.; Aldous, D. J.; Aldous, S. C. JOC 1992, 57, 6527.
6. Burdisso, M.; Gandolfi, R.; Grunanger, P.; Rastelli, A. JOC 1990, 55, 3427.
7. Goe, G. L. JOC 1973, 38, 4285.
8. Johnson, C. R.; De Jon, R. JOC 1992, 57, 594.
9. (a) Araki, Y.; Endo, T.; Tanji, M.; Nagasawa, J.; Ishido, Y. TL 1988, 29, 351. (b) Araki, Y.; Endo, T.; Tanji, M.; Arai, Y.; Ishido, Y. TL 1988, 29, 2335. (c) Araki, Y.; Endo, T.; Arai, Y.; Tanji, M.; Ishido, Y. TL 1988, 29, 5297. (d) Araki, Y.; Endo, T.; Tanji, M.; Nagasawa, J. TL 1987, 28, 5853.
10. (a) Harvey, R. G. T 1966, 22, 2561. (b) Trost, B. M.; Melvin, L. S. JACS 1976, 98, 1204.

Gary A. Sulikowski & Michelle M. Sulikowski

Texas A&M University, College Station, TX, USA



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