Chlorine Fluoroxysulfate1

ClOSO2F

[13637-84-8]  · ClFO3S  · Chlorine Fluoroxysulfate  · (MW 134.51)

(strong electrophilic chlorinating agent, capable of halogen abstraction reactions to give esters of fluorosulfuric acid,1-7 of electrophilic additions8-11 and substitutions12-14)

Physical Data: colorless liquid; mp -84.3 °C; bp 45.1 °C.1

Preparative Methods: can be obtained either by the reaction of peroxydisulfuryl difluoride (F2S2O6) with Cl23,15 or by insertion of SO3 into ClF.16,17

Handling, Storage, and Precautions: stable and is not explosive.1 However, it can ignite organic materials upon contact (including nonperfluorinated grease).4 It is hydrolyzed by water to give HCl and fluorosulfuric acid. This reagent should be handled in a fume hood.

Synthesis of Fluorosulfates.

The chemical behavior of ClOSO2F (1) is determined by its ability to serve as a Cl+ synthon.1 It smoothly substitutes halogen atoms (Cl, Br, I) for fluorosulfate groups (eq 1).1-7

For example, 1,2-dichloroethane or alkylchloroacetates react with (1) at -40 °C to 0 °C to give the corresponding fluorosulfates (eq 2).5

Geminal chlorine atoms can be substituted to give gem-difluorosulfates, for example eq 3.3

The addition of fluorosulfuric acid2,3 or bromine7 catalyzes the reactions. In the case of mustard gas and its analogs, S[(CH2)nCl]2, the reaction with (1) gives the corresponding bis-fluorosulfates, while the sulfur atom undergoes chlorination to give Cl4S[(CH2)nOSO2F]2.6 Perfluoroalkyl bromides are also readily transformed into the corresponding fluorosulfates, RfOSO2F.2,7 In the case of perfluoroalkyl iodides the relatively stable derivatives of type RfI(OSO2F)2 can be isolated.1,7

Perfluoroalkenes, fluorochloroalkenes, and chloroalkenes react with (1) to give b-chlorofluorosulfates (eq 4).8-11

Hexafluorobenzene, C6F6, also gives a 1,4-addition product and then the 1,2,3,4,5,6-addition product.9 Addition to the C&tbond;C bond gives mono- and diadducts.11

Nitrile groups can add 1 mol of (1) in accordance with eq 5.4,18

Reaction of (1) with N-chlorodifluoromethanimine gives the corresponding diazene (eq 6).19

Chlorination.

The electrophilic chlorination of various organic substrates is a typical reaction of (1), the reagent serving as the source of Cl+. Alcohols and carboxylic acids react with (1) to give the corresponding hypochlorites (eq 7).1 The reaction yields are variable and are determined by the stability of the final products.1

This process was applied to the synthesis of inorganic hypochlorites, for example TeF5OH -> TeF5OCl.20

Reagent (1) is also a powerful chlorinating agent for aromatic substitutions.12,13 For example, benzene gives hexachlorobenzene even at -100 °C.12 In the presence of SbF5 the reagent (1) chlorinates the pentafluorobenzene, C6HF5, into chloropentafluorobenzene, C6ClF5.14

Perfluoronitroso compounds undergo substitution of the nitroso group by chlorine (eq 8).21

Related Reagents.

Peroxydisulfuryl Difluoride.


1. Fokin, A. V.; Studnev, Yu. N.; Kuznetzova, L. D.; Krotovich, I. N. Usp. Khim. 1982, 51, 1258 (CA 1982, 97, 181 258m).
2. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Tatarinov, A. S.; Serjanov, Yu. V. IZV 1985, 1635 (CA 1986, 104, 185 942r).
3. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Kuznetzova, L. D.; Verenikin, O. V.; Krotovich, I. N. IZV 1976, 2422 (CA 1977, 86, 89 108n).
4. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Kuznetzova, L. D.; Komarov, V. A. IZV 1976, 489 (CA 1976, 85, 20 539r).
5. Fokin, A. V.; Studnev, Yu. N.; Krotovich, I. N.; Kuznetzova, L. D.; Verenikin, O. V. IZV 1979, 806 (CA 1979, 91, 19 832y).
6. Chilikin, V. G.; Stolyarov, V. P.; Burov, M. K.; Emelyanov, V. I.; Studnev, Yu. N. Soviet Union Patent 1 657 493, 1991 (CA 1992, 116, 151 142n).
7. Schack, C. J.; Christe, K. O. JFC 1980, 16, 63.
8. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Nguen Tche Hgem; Zagorevskyi, D. V. IZV 1984, 1572 (CA 1985, 102, 78 305x).
9. Fokin, A. V.; Studnev, Yu. N.; Kuznetzova, L. D.; Krotovich, I. N. IZV 1978, 649 (CA 1978, 89, 42 326d).
10. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Krotovich, I. N.; Kuznetzova, L. D.; Komarov, V. A. IZV 1976, 946 (CA 1976, 85, 62 723b).
11. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Krotovich, I. N.; Verenikin, O. V. IZV 1985, 1094 (CA 1985, 103, 214 819t).
12. Fokin, A. V.; Studnev, Yu. N.; Krotovich, I. N.; Kuznetzova, L. D.; Gukov, A. M. IZV 1977, 2388 (CA 1978, 88, 89 228t).
13. Fokin, A. V.; Nikolaeva, A. D.; Studnev, Yu. N.; Proshin, N. A.; Leonov, A. G. IZV 1982, 1160 (CA 1982, 97, 72 004e).
14. Fokin, A. V.; Studnev, Yu. N.; Krotovich, I. N.; Furin, G. G.; Yakobson, G. G. IZV 1981, 927 (CA 1981, 95, 114 932x).
15. Gilbreath, W. P.; Cady, G. H. IC 1963, 2, 496.
16. Schack, C. J.; Wilson R. D. IC 1970, 9, 311.
17. Gillespie, R. J.; Morton, M. J. IC 1972, 11, 591.
18. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Krotovich, I. N.; Verenikin, O. V. IZV 1981, 2370 (CA 1982, 96, 51 783x).
19. Zheng, Y. Y.; Bauknight, C. W., Jr.; DesMarteau, D. D. JOC 1984, 49, 3590.
20. Schack, C. J.; Christie, K. O. JFC 1982, 21, 393.
21. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Krotovich, I. N.; Chilikin, V. G.; Verenikin, O. V. IZV 1984, 832 (CA 1984, 101, 130 177c).

Nikolai S. Zefirov

Moscow State University, Russia



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