Silver(I) p-Toluenesulfonate

[16836-95-6]  · C7H7AgO3S  · Silver(I) p-Toluenesulfonate  · (MW 279.08)

(mild Lewis acid with a high affinity for organic halides)

Solubility: sol acetonitrile, diethyl ether, water.

Form Supplied in: white solid; widely available.

Analysis of Reagent Purity: contents of Ag can be assayed conveniently by volumetric titration of AgI.

Preparative Method: can be prepared by mixing aqueous solutions of Silver(I) Nitrate and sodium tosylate and filtering off the precipitate.

Handling, Storage, and Precautions: should be protected from light.

Conversion of Alkyl Halides into Tosylates.

Treatment of primary alkyl halides, in most cases bromides and iodides, with silver tosylate in acetonitrile, gives good yields of the corresponding tosylates.1,2 Tertiary and benzylic tosylates, even though they are very prone to dissociate, have been prepared using a similar procedure.3

Solvolysis of Reactive Halides.

In analogy with other silver(I) salts, this reagent has been used for solvolysis of reactive bromides. Thus treatment of bicyclic geminal dibromocyclopropanes leads to ring-enlarged products (eq 1). The stereoselectivity observed indicates that a concerted electrocyclic ring opening is involved.4 Analogously, benzylic bromides have been shown to give styrenes on treatment with AgOTs in dichloromethane.5

Synthesis via Benzeneselenenyl Tosylate.

Treatment of Benzeneselenenyl Chloride with AgOTs in acetonitrile gives the unstable benzeneselenenyl tosylate. This reagent (prepared in situ) adds to alkynes to give b-(phenylseleno)vinyl tosylates (eq 2).6

Related Reagents.

Silver(I) Tetrafluoroborate.

1. Emmons, W. D.; Ferris, A. F. JACS 1953, 75, 2257.
2. Kornblum, N.; Jones, W. J.; Anderson, G. J. JACS 1959, 81, 4113.
3. Hoffman, H. M. R. JCS 1965, 6748.
4. Loozen, H. J. J.; Robben, W. M. M.; Richter, T. L.; Buck, H. M. JOC 1976, 41, 384.
5. Oki, M.; Shionoiri, K.; Otake, K.; Ono, M.; Toyota, S. BCJ 1993, 66, 589.
6. Back, T. G.; Muralidharan, K. R. JOC 1991, 56, 2781.

Lars-G. Wistrand

Nycomed Innovation, Malmö, Sweden

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