[67-72-1]  · C2Cl6  · Hexachloroethane  · (MW 236.72)

(mild chlorinating agent;1,2 versatile reagent in organophosphorus chemistry3-5)

Alternate Name: perchloroethane.

Physical Data: mp 190-195 °C (sublimes); d 2.091 g cm-3; rhombohedric crystals from EtOH.

Solubility: insol H2O; sol organic solvents.

Form Supplied in: white solid; widely available.

Purification: steam distillation, then recrystallization from 95% EtOH.20

Handling, Storage, and Precautions: cancer suspect agent; irritant. Use in a fume hood.

Chlorination of Carbon Compounds.

Hexachloroethane is a formal source of electrophilic chlorine in the chlorination of nucleophiles.1,2 The reagent can conveniently be used in large-scale reactions.6 THF7-11 is the solvent of choice for chlorination of aryllithiums (eqs 1 and 2).

The reactions with Wittig reagents (eq 3) are usually conducted in ether,12 and sulfoximine derivatives are chlorinated by Cl3CCCl3 in DMF.13 Phase-transfer conditions are recommended for chlorination of allyl sulfones (eq 4)14,15 and benzyl and benzal chlorides (eq 5).6

In a typical reaction, a mixture of equimolar amounts of the substrate and Cl3CCCl3, dichloromethane, 50% aq NaOH, and a catalytic amount of tetrabutylammonium bromide (TBAB) is stirred at rt.15 The phase-transfer catalysis can be aided by sonication in the synthesis of gem-bromochlorocyclopropanes by the reaction of an alkene, Bromoform, and Cl3CCCl3 in the presence of powdered Sodium Hydroxide.16

Reactions with Organophosphorus Compounds.3-5

The important applications of Cl3CCCl3 in organophosphorus chemistry are the syntheses of 1-chloro-2-phenyl-2-(trimethylsilyl)-1-phosphaethylene (eq 6),3,4 tetraphosphacubanes (eq 7),17 and trans-1,2,4,5-tetraphosphatricyclo[,4]hexane (eq 8).18

A combination reagent, Hexamethylphosphorous Triamide-Cl3CCCl3-1-Hydroxybenzotriazole, has been used in the synthesis of oligopeptides containing arginine.19

Related Reagents.

t-Butyl Hypochlorite; Chlorine; Chlorine-Chlorosulfuric Acid; Dimethyl Sulfide-Chlorine; Chlorine Fluoroxysulfate; Chlorine-Pyridine; N-Chlorosuccinimide; Dichlorine Monoxide; Phosphorus(III) Chloride; Sulfuryl Chloride.

1. Lipshutz, B. H.; Hagen, W. TL 1992, 33, 5865.
2. Boeckman, R. K., Jr.; Perni, R. B.; Macdonald, J. E.; Thomas, A. J. OS 1988, 66, 194; OSC 1993, 8, 192.
3. Appel, R.; Kundgen, U.; Knoch, F. CB 1985, 118, 1352.
4. Appel, R.; Geisler, K.; Scholer, H. E. CB 1977, 110, 376, and references cited therein.
5. Appel, R.; Barth, V.; Knoch, F. CB 1983, 116, 938.
6. Chupp, J. P.; Grabiak, R. C.; Leschinsky, K. L.; Neumann, T. L. S 1986, 224.
7. Hommes, H.; Verkruijsse, H. D.; Brandsma, L. TL 1981, 22, 2495.
8. Krizan, T. D.; Martin, J. C. JOC 1982, 47, 2681.
9. Svensson, A.; Martin, A. R. H 1985, 23, 357.
10. Iwao, M.; Kuraishi, T. H 1992, 34, 1031.
11. Fugina, N.; Holzer, W.; Wasicky, M. H 1992, 34, 303.
12. Li, X.-Y.; Hu, J.-S. TL 1987, 28, 6317.
13. Johnson, C. R.; Tangerman, A. S 1982, 286.
14. (a) Jonczyk, A.; Radwan-Pytlewski, T. CL 1983, 1557; (b) Kattenberg, J.; de Waard, E. R.; Huisman, H. O. T 1973, 29, 4149; (c) Burger, J. J.; Chen, T. B. R. A.; de Waard, E. R.; Huisman, H. O. T 1980, 36, 1847; (d) Dehmlow, E. V.; Dehmlow, S. S. Phase Transfer Catalysis; Verlag Chemie: Weinheim, 1980; (e) Makosza, M. In Survey of Progress in Chemistry; Scott, A. F., Ed.; Academic: New York, 1980; Vol. 9, p 1.
15. Jonczyk, A.; Radwan-Pytlewski, T. JOC 1983, 48, 910.
16. Xu, L.; Tao, F. SC 1988, 18, 2117.
17. Wettling, T.; Geissler, B.; Schneider, R.; Barth, S.; Binger, P.; Regitz, M. AG(E) 1992, 31, 758.
18. Niecke, E.; Streubel, R.; Nieger, M. AG(E) 1991, 30, 90.
19. Appel, R.; Heister, E. CB 1981, 114, 2649.
20. Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory Chemicals, 3rd ed.; Pergamon: New York, 1988; p 192.

Lucjan Strekowski & Alexander S. Kiselyov

Georgia State University, Atlanta, GA, USA

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