[10140-89-3]  · C3H4Cl2O  · 2,3-Dichloropropionaldehyde  · (MW 126.97)

(undergoes condensation reactions, ene reactions, 1,2-additions; a-chloro nitrone precursor)

Alternate Name: 2,3-dichloropropanal.

Physical Data: bp 45 °C/12 mmHg; nD20 1.4762; d20 1.3712 g cm-3.

Solubility: sol most common organic solvents such as hexane, ether, THF, methylene chloride, ethanol, etc.

Form Supplied in: colorless liquid; not commercially available.

Analysis of Reagent Purity: NMR.

Preparative Methods: the reagent is best prepared by bubbling an equimolar amount of dry Chlorine gas into neat Acrolein at 5 °C.2 The reaction temperature thereby rises spontaneously and is kept at 40 °C until the reaction has ended. Spinning band distillation at reduced pressure (12 mmHg) affords pure 2,3-dichloropropionaldehyde as a colorless liquid in 65% yield.

Handling, Storage, and Precautions: as the reagent is prone to polymerization it should be used as prepared for best results. For a limited time it can be stored under nitrogen at 5 °C in tightly sealed bottles. Use in a fume hood.

Condensation Reactions.

In the presence of Lewis acid catalysts such as Aluminum Chloride or Tin(IV) Chloride, 2,3-dichloropropionaldehyde undergoes ene reactions1 with acyclic3-5 and cyclic alkenes6,7 to afford alkenyl-substituted dichlorohydrins (eqs 1 and 2), which after treatment with base can easily be converted to the corresponding epichlorohydrins (eq 1).6 With unsymmetrical alkenes such as 1-methylcyclohexene a mixture of products is obtained (eq 2),7 in which the regioisomer resulting from methylene hydrogen abstraction dominates.

Asymmetric induction (70-75% ee) has been achieved in this ene reaction if a chiral catalyst such as (-)-menthoxyaluminum dichloride is employed.4 In the absence of alkenes, Lewis acids such as AlCl3 or Triethylaluminum initiate at low temperature the polymerization of the reagent to give high molecular weight poly[oxy(2,3-dichloropropylidene)].8

Similarly substituted dichlorohydrins or epichlorohydrins can also be generated by the addition of Grignard reagents to 2,3-dichloropropionaldehyde (eq 3).9,10

Precursor to Other Reagents.

Besides its role as precursor for the preparation of 2-chloroacrolein or its diethyl acetal (eq 4),2 the reagent has also served as an intermediate to 2,3-dichloro-N-cyclohexylpropanaldonitrone.11 The latter, which is formed upon treatment of the reagent with N-cyclohexylhydroxylamine, is able to undergo Ag+-induced stereospecific cis additions to isolated double bonds,11 thus formally entering a Diels-Alder reaction with inverse electron demand. The resulting cyanide-trapped addition products are obtained as diastereomeric mixtures, which then may be converted in two steps to a-methylene-g-butyrolactones in good yields (eq 5), thereby providing a preparative route to this unit often encountered in natural products. When the same a,b-dichloro nitrone is combined with a quinoidal vinologous ester system, an unusual course of the cycloaddition reaction is observed.12

Finally, 2,3-dichloropropionaldehyde has also served as a precursor for the preparation of pyrazoles13 and a new type of phosphorus-containing betaine.14

1. Snider, B. B. ACR 1980, 13, 426.
2. (a) Shostakovskii, M. F.; Annenkova, V. Z.; Ivanova, L. T.; Ugryumova, G. S. IZV 1967, 6, 104 (CA 1968, 69, 51 483s). (b) Andreeva, I. V.; Koton, M. M.; Akopova, A. N.; Kukarkina, N. V. ZOR 1975, 11, 954 (CA 1975, 83, 42 773y).
3. Sadykh-Zade, Z. I.; Akhmedov, M. A.; Mamedov, G. K. Dokl. Akad. Nauk Azerb. SSR 1973, 29, 24 (CA 1974, 80, 120 651m).
4. Akhmedov, M. A.; Akhmedov, I. M.; Musaeva, K. E.; Sardarov, I. K.; Kostikov, R. R.; Menchikov, L. G. ZOR 1991, 27, 2297 (CA 1992, 116, 235 046x).
5. Sadykh-Zade, S. I.; Akhmedov, M. A.; Kyazimov, S. K.; Mustafaeva, Z. G.; Svergun, V. I. ZOR 1977, 13, 2447 (CA 1978, 88, 62 252j).
6. Sadykh-Zade, S. I.; Akhmedov, M. A.; Mustafaeva, Z. G. Uch. Zap.-Minist. Vyssh. Sredn. Spets. Obraz. Az. SSR, Ser. Khim. Nauk 1975, 42 (CA 1976, 85, 142 931h).
7. Sadykh-Zade, S. I.; Akhmedov, M. A.; Kyazimov, S. K.; Mustafaeva, Z. G.; Guseinova, L. S. Azerb. Khim. Zh. 1976, 35 (CA 1977, 87, 52 842s).
8. Sumitomo, H.; Nakagawa, T. J. Polym. Sci. B. 1969, 7, 739.
9. Dhami, K. S. IJC 1974, 12, 278.
10. Shigeo, T.; Shinichi, Y. Yuki Gosei Kagaku Kyokai Shi 1971, 29, 530 (CA 1972, 76, 34 603h).
11. Petrzilka, M.; Felix, D.; Eschenmoser, A. HCA 1973, 56, 2950.
12. Hepp, L. R.; Bordner, J.; Bryson, T. A. TL 1985, 26, 595.
13. Henneke, K. W.; Wedemeyer, K.; Fiege, H. Ger. Patent 3 122 261, 1982 (CA 1983, 98, 107 285x).
14. Gololobov, Y. G.; Kim, T. V.; Kiseleva, E. I. DOK 1983, 272, 1388 (CA 1984, 100, 103 483x).

Martin Petrzilka

Givaudan-Roure Research, Dübendorf, Switzerland

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