Benzeneselenenyl Trifluoromethanesulfonate1

[112238-64-9]  · C7H5F3O3SSe  · Benzeneselenenyl Trifluoromethanesulfonate  · (MW 305.13)

(a highly electrophilic selenium reagent2-8)

Alternate Name: benzeneselenenyl triflate.

Preparative Methods: usually prepared in situ by the reaction of Benzeneselenenyl Chloride with Silver(I) Trifluoromethanesulfonate in dichloromethane or toluene.2 Two other economical methods are available. The first is the removal of hydrogen chloride from a mixture of benzeneselenenyl chloride and Trifluoromethanesulfonic Acid.3 The second is the comproportionation reaction of benzeneseleninic anhydride (see Benzeneseleninic Acid) and Diphenyl Diselenide in the presence of trifluoromethanesulfonic anhydride.4

Handling, Storage, and Precautions: moisture sensitive. The dichloromethane solution free of silver chloride and water can be stored at rt for several weeks in the dark.3

Addition Reactions.

Benzeneselenenyl triflate is a highly electrophilic selenium reagent due to the poor nucleophilicity of triflate anion. It adds to alkenes having an intramolecular carboxy or hydroxy group to give cyclic products. For example, g,d-unsaturated carboxylic acids react with benzeneselenenyl triflate in dichloromethane to give g-lactones in high yields (eq 1).2 Under similar reaction conditions, 5- and 6-hydroxyalkenes are transformed to exo-cyclized tetrahydrofuran or -pyran derivatives (eq 2).5,6 This reaction is useful for one-step conversion of acyclic terpene alcohols and derivatives into mono- or polycyclic compounds.7 In the reaction with phenylacetylene, benzeneselenenyl triflate gives a trans adduct, a vinyl triflate, in high yield, which can be easily hydrolyzed to the ketone (eq 3).4

Selenium Polonovski Reaction.

Amine N-oxides react with benzeneselenenyl triflate to form selenoxyammonium salts, which rearrange to a-selenoxyamines in the presence of organic bases.3 The products can be easily converted into secondary or tertiary amine derivatives (eq 4).

O-Glycosylation.

Alcohols efficiently undergo O-glycosylation under mild conditions by treatment with 1-thioglycosides and benzeneselenenyl triflate (eq 5).8 This reaction can be applied to stereo- and regioselective synthesis of a-cyclodextrin derivatives.9

Related Reagents.

Benzeneselenenyl m-nitrobenzenesulfonate,10a benzeneselenenyl p-toluenesulfonate,10b (phenylseleno)dimethylsulfonium (PhSe+SMe2) fluoroborate,11 and (phenylseleno)methylphenylselenonium (PhSe+SeMePh) fluoroborate12 can be considered as analogs of benzeneselenenyl triflate. (Phenylseleno)dimethylsulfonium (PhSe+SMe2) fluoroborate reacts with electron-rich aromatic compounds to give the products of electrophilic substitution (eq 6).11 On the other hand, (phenylseleno)methylphenylselenonium (PhSe+SeMePh) fluoroborate reacts selectively with allylic silanes to give the corresponding allylic selenides, which easily undergo 2,3-sigmatropic rearrangement to allylic alcohols by oxidation (eq 7).12

See also Benzeneselenenyl Bromide, Benzeneselenenyl Chloride, Benzenesulfenyl Chloride, and 2-Pyridinesulfenyl Bromide.


1. Reviews and books on organoselenium reagents. (a) Clive, D. L. J. T 1978, 34, 1049. (b) Reich, H. J. ACR 1979, 12, 22. (c) Nicolaou, K. C.; Petasis, N. A. Selenium in Natural Products Synthesis; CIS: Philadelphia, 1984. (d) The Chemistry of Organic Selenium and Tellurium Compounds; Patai, S; Rappoport, Z., Eds.; Wiley: New York, 1986; Vol. 1. (e) Paulmier, C. Selenium Reagents and Intermediates in Organic Synthesis; Pergamon: Oxford, 1986. (f) Organoselenium Chemistry; Liotta, D. Ed.; Wiley: New York, 1987.
2. Murata, S.; Suzuki, T. CL 1987, 849.
3. Okazaki, R.; Itoh, Y. CL 1987, 1575.
4. Kutateladze, A. G.; Kice, J. L.; Kutateladze, T. G.; Zefirov, N. S.; Zyk, N. V. TL 1992, 33, 1949.
5. Murata, S.; Suzuki, T. TL 1987, 28, 4297.
6. Murata, S.; Suzuki, T. TL 1987, 28, 4415.
7. Murata, S.; Suzuki, T. TL 1990, 31, 6535.
8. Ito, Y.; Ogawa, T. TL 1988, 29, 1061.
9. Mori, M.; Ito, Y.; Ogawa, T. TL 1990, 31, 3029.
10. (a) Yoshida, M.; Satoh, N.; Kamigata, N. CL 1989, 1433. (b) Back, T. G.; Muralidharan, K. R. JOC 1991, 56, 2781.
11. Gassman, P. G.; Miura, A.; Miura, T. JOC 1982, 47, 951.
12. (a) Vedejs, E.; Rodgers, J. D.; Wittenberger, S. J. TL 1988, 29, 2287. (b) Vedejs, E.; Ahmad, S. TL 1988, 29, 2291.

M. Iwaoka & S. Tomoda

The University of Tokyo, Japan



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