[2314-97-8]  · CF3I  · Trifluoroiodomethane  · (MW 195.91)

(trifluoromethylating reagent)

Alternate Name: trifluoromethyl iodide.

Physical Data: bp -22 °C.1

Solubility: sol ether, acetone, alcohol, benzene.

Form Supplied in: gas; commercially available.

Preparative Methods: prepared by the fluorination of CI4 with IF5 (eq 1),2 or by the Hunsdiecker reaction of Silver(I) Trifluoroacetate with an excess of Iodine (eq 2),3 or by the reaction of trifluoroacetyl fluoride with Lithium Iodide (eq 3).4 More recently, Chen reported a convenient method for the synthesis of CF3I by the reaction of XCF2CO2Me (X = Br, Cl) with iodine, KF, and CuI (eq 4).5

Addition to Alkenes and Alkynes.

Radical addition of CF3I to alkenes and alkynes is initiated by irradiation,6 peroxide,6a metals,7 boranes,8 enzymes,9 and heating10 to give the corresponding adducts (eq 5). Enamines react with CF3I rapidly at room temperature without UV irradiation or initiator to form trifluoromethylated ketones after hydrolysis.11

Addition to Carbonyl Compounds.

Addition of CF3I to carbonyl compounds is promoted by metals and metal salts such as Zinc,12 Zn/MV2+ (MV2+ = methyl viologen),13 Tin(II) Chloride,14 Zn/ultrasound,15 and Magnesium16 to form the corresponding trifluoromethylated alcohols (eq 6).

Coupling with Organic Halides.

In the presence of copper metal, CF3I undergoes coupling with aryl and vinyl iodides to afford the corresponding trifluoromethylated aromatics and alkenes, respectively.17 Pregenerated CF3Cu (from the reaction of CF3I with copper metal in HMPA at 120 °C) reacts with benzyl, allyl, vinyl, acyl, and alkyl bromides to give the corresponding trifluoromethylated products (eq 7).18

Reaction with Thiolates.

Photoreaction of CF3I with thiols in liquid NH3 gives the corresponding trifluoromethyl sulfides (eq 8).19

Addition to Aromatic Compounds.

Trifluoromethylation of benzene, thiophene, pyridine, and imidazole has been accomplished via thermolysis or irradiation of CF3I in the presence of the appropriate aromatic compound (eq 9).20

1. Kudchadker, A. P.; Kudchadker, S. A.; Shukla, R. P.; Patnaik, P. R. J. Phys. Chem. Ref. Data 1979, 8, 499.
2. Banks, A. A.; Emeleus, H. J.; Haszeldine, R. N.; Kerrigan, V. JCS 1948, 2188.
3. (a) Henne, A. L.; Finnegan, W. G. JACS 1950, 72, 3806. (b) Hauptschein, M.; Grosse, A. V. JACS 1951, 73, 2461.
4. Fukaya, H.; Abe, T.; Hayashi, E. CL 1990, 813.
5. Su, D.-B.; Duan, J.-X.; Chen, Q.-Y. CC 1992, 807.
6. (a) Henne, A. L.; Kraus, D. W. JACS 1951, 73, 1791. (b) Haszeldine, R. N.; Steele, B. R. JCS 1953, 1592.
7. (a) Fuchikami, T.; Ojima, I. TL 1984, 25, 303. (b) Fujita, K.; Kobayashi, S.; Kudo, I.; Inoue, K.; Nojima, S.; Ohno, M.; Kobayashi, Y.; Odagiri, M.; Taguchi, T. CPB 1987, 35, 647. (c) Pazenok, S. V.; Chaika, E. A.; Gerus, I. I.; Yagupol'skii, L. M. JOU 1989, 25, 1238.
8. Sugimoto, J.; Miura, K.; Oshima, K.; Utimoto, K. CL 1991, 1319.
9. Kitazume, T.; Ikeya, T. JOC 1988, 53, 2350.
10. Henne, A. L.; Nager, M. JACS 1951, 73, 5527.
11. Cantacuzene, D.; Wakselman, C.; Dorme, R. JCS(P1) 1977, 1365.
12. Lang, R. W. HCA 1988, 71, 369.
13. Kitazume, T.; Ikeya, T. JOC 1988, 53, 2349.
14. Kitazume, T.; Ishikawa, N. CL 1981, 1337.
15. Kitazume, T.; Ishikawa, N. CL 1981, 1679.
16. McBee, E. T.; Battershell, R. D.; Braendlin, H. P. JOC 1963, 28, 1131.
17. (a) McLoughlin, V. C. R.; Thrower, J. T 1969, 25, 5921. (b) Lin, T.-S.; Gao, Y.-S. JMC 1983, 26, 598.
18. Kobayashi, Y.; Yamamoto, K.; Kumadaki, I. TL 1979, 4071.
19. Boiko, V. N.; Shchupak, G. M.; Ignat'ev, N. V.; Yagupol'skii, L. M. JOU 1979, 15, 1111.
20. (a) Cowell, A. B.; Tamborski, C. JFC 1981, 17, 345. (b) Kobayashi, Y.; Kumadaki, I.; Ohsawa, A.; Murakami, S.-I.; Nakano, T. CPB 1978, 26, 1247. (c) Kimoto, H.; Fujii, S.; Cohen, L. A. JOC 1984, 49, 1060.

Donald J. Burton & Weiming Qui

The University of Iowa, Iowa City, IA, USA

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