[534-07-6]  · C3H4Cl2O  · 1,3-Dichloroacetone  · (MW 126.97)

(starting material for the synthesis of cyclopropanols2 and cyclopropenones3)

Alternate Name: 1,3-dichloro-2-propanone.

Physical Data: mp 39-41 °C; bp 173 °C; d 1.383 g cm-3.

Solubility: sol organic solvents.

Form Supplied in: solid; commercially available.

Handling, Storage, and Precautions: highly corrosive and toxic. Use in a fume hood.

The reagent is useful as starting material for a simple one-pot synthesis of many 1-arylcyclopropanols (eq 1).4,5 In this procedure the initially formed 1,3-dichloro-2-aryl isopropoxide is reduced to the 1-aryl cyclopropoxide by low-valent iron, generated in situ by the reaction of Ethylmagnesium Bromide with Iron(III) Chloride.6 The general method can be extended to the synthesis of 1-alkylcyclopropanols by using an excess of Lithium powder as the reducing agent in place of the EtMgBr/FeCl3.7 A somewhat related synthesis of 1-alkyl- or 1-arylcyclopropanols makes use of the reaction of ethyl 3-bromopropionate with 1 equiv of Grignard reagent in the presence of 2 equiv of Samarium(II) Iodide.8

1,3-Dichloroacetone also serves as the starting reagent in a general synthesis of cyclopropenones and their acetals (eq 2).3 The initially formed cyclopropenone acetal (1) can be alkylated a second time if desired, and then hydrolyzed to a dialkylcyclopropenone.

1. No review of the chemistry of 1,3-dichloroacetone has been published. For a review of the chemistry of cyclopropanols, see: Gibson, D. H.; DePuy, C. H. CRV 1974, 74, 605. For a review of the chemistry of cyclopropenones, see: Potts, K. T.; Baum, J. S. CRV 1974, 74, 189.
2. DePuy, C. H.; Klein, R. A. OS 1967, 47, 108.
3. Isaka, M.; Ejiri, S.; Nakamura, E. T 1992, 48, 2045.
4. DePuy, C. H.; Dappen, G. M.; Eilers, K. L.; Klein, R. A. JOC 1964, 29, 2813.
5. Brown, H. C.; Rao, C. G. JOC 1978, 43, 3602.
6. Kochi, J. K.; Singleton, D. M. JOC 1968, 33, 1027.
7. Barleunga, J.; Alonso-Cires, L.; Campos, P. J.; Asensio, G. S 1983, 649.
8. Fukuzawa, S.; Niimoto, Y.; Sakai, S. TL 1991, 32, 7691.

Charles H. DePuy

University of Colorado, Boulder, CO, USA

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