[18214-55-6]  · C6H8Br2  · 2,3-Bis(bromomethyl)-1,3-butadiene  · (MW 239.94)

(Diels-Alder diene;1 preparation of other 2,3-disubstituted 1,3-dienes2)

Physical Data: mp 57-58 °C.

Solubility: sol pentane, THF.

Form Supplied in: white solid.

Preparative Methods: Zn-Cu1 or Sn-Cu3 mediated dehalogenation of tetrakis(bromomethyl)ethylene; thermolysis of a precursor sulfone;3 and through reaction of allene with PdBr2.4,5

Purification: recrystallization from pentane,1 hexane,6 or hexane-ethyl acetate.5

Handling, Storage, and Precautions: light sensitive; tends to polymerize at room temperature. Stable for months when stored as a solid or as a solution in ether in the dark at 0 °C.

Diels-Alder Diene.

The primary synthetic uses of 2,3-bis(bromomethyl)-1,3-butadiene (1) are in Diels-Alder chemistry, in preparation of heterocycles, in the preparation of p-allyl organometallic complexes,7 and in polymer chemistry. The reactivity of (1) is not unlike that of other 1,3-dienes and allylic halides. Diels-Alder reaction of (1) with benzoquinone leads to dihydronaphthoquinone (2) in 69% yield (eq 1).8

Electron deficient alkynes and diazo compounds are also active Diels-Alder partners (eq 2).2 Diels-Alder reaction of (1) with Diethyl Azodicarboxylate (DEAD) leads to (3). Similarly, treatment of (1) with Dimethyl Acetylenedicarboxylate (DMAD) leads to (4).1 Debromination of these allylic bromides with zinc-copper couple results in the formation of new 1,3-dienes that can be used in additional Diels-Alder reactions.1

2,3-Disubstituted 1,3-Dienes.

Treatment of (1) with a variety of nucleophiles leads to mono- or dialkylation (eq 3). Symmetrical 2,3-disubstituted butadienes (5) result1,9 from reaction of (1) with NaOMe, NaOAc, NaN3, or KCN, and further elaboration of these dienes has been accomplished. Addition of unstabilized carbon nucleophiles such as vinylmagnesium chloride leads to polyenes.1

Treatment of tertiary diamines leads to the formation of polyelectrolytes (eq 4).6


Treatment of (1) with other anions such as Na2S,10 NaOH in DMSO,9 Na2Se,11 RNH2 (R = alkyl or aryl),9 or stabilized carbanions2 produces bis(methylene) heterocycles (6) (eq 5). There are examples of heterocycles resulting from the treatment of (1) with diamines.12

Heterocycles (6) participate in Diels-Alder reactions,2 as well as undergoing (in some cases) intramolecular photochemical [2 + 2] reactions to form [3.2.0]bicyclic systems.1 Several of the 3,4-dimethylenepyrrolidine compounds have been used as monomers in the synthesis of polypyrroles.13,14

1. Gaoni, Y.; Sadeh, S. JOC 1980, 45, 870.
2. Commerçon, A.; Ponsinet, G. TL 1985, 26, 4093.
3. Dowd, P.; Marwaha, L. K. JOC 1976, 41, 4035.
4. Hegedus, L. S.; Kambe, N.; Ishii, Y.; Mori, A. JOC 1985, 50, 2240.
5. Ali, S. M.; Tanimoto, S.; Okamoto, T. JOC 1988, 53, 3639.
6. Ottenbrite, R. M.; Myers, G. R. Macromol. Synth. 1982, 8, 13.
7. Sadeh, S.; Gaoni, Y. JOM 1975, 93, C31.
8. Butler, G. B.; Ottenbrite, R. M. TL 1967, 4873.
9. Gaoni, Y. TL 1973, 2361.
10. Sadeh, S.; Gaoni, Y. TL 1973, 2365.
11. Mazerolles, P.; Laurent, C. JOM 1991, 402, 35.
12. Ottenbrite, R. M.; Yoshimatsu, A.; Smith, J. G., Jr. Polym. Adv. Technol. 1990, 1, 117.
13. Ottenbrite, R. M.; Smith, J. G., Jr. Polym. Prepr. 1988, 29, 263.
14. Ottenbrite, R. M.; Chen, H. Polym. Prepr. 1983, 24, 366.

Mark S. Meier

University of Kentucky, Lexington, KY, USA

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