Sulfur Trioxide-Pyridine

[26412-87-3]  · C5H5NO3S  · Sulfur Trioxide-Pyridine  · (MW 159.18)

(forms sulfate esters which can be displaced with hydride; useful in displacement reactions of allylic alcohols which cannot be converted to halides; used with DMSO for oxidation of alcohols)

Physical Data: mp 175 °C.

Solubility: sol DMSO; slightly sol ether, CHCl3, CCl4.

Form Supplied in: crystalline white solid; widely available.

Preparative Methods: reaction of Chlorosulfonic Acid and Pyridine in CHCl31a,b or reaction of Sulfur Trioxide and pyridine.1c

Handling, Storage, and Precautions: corrosive; reacts quantitatively with hot H2O to give pyridine and sulfuric acid. Use in a fume hood.

General Discussion.

Addition of the title complex to farnesol (1) in THF at 0 °C and stirring of the suspension results in formation of the sulfate (2) (eq 1). Addition of Lithium Aluminum Hydride in THF then gives the hydrocarbon (3) (eq 2). 2a Other alcohols are converted similarly.2 Reaction with glucose gave glucose-6-sulfate (4) isolated as the barium salt (eq 3).3a Sulfonation of indole occurs on treatment with the reagent (eq 4).3b

Related Reagents.

Dimethyl Sulfoxide-Sulfur Trioxide/Pyridine; Sulfur Trioxide; Sulfur Trioxide-1,4-Dioxane.


1. (a) Sisler, H. H.; Audrieth, L. F. Inorg. Synth. 1946, 2, 173. (b) Fieser, L. F. JACS 1948, 70, 3232. (c) Baumgarten, P. CB 1926, 59, 1166.
2. (a) Corey, E. J.; Achiwa, K. JOC 1969, 34, 3667. (b) Corey, E. J.; Cane, D. E.; Libit, L. JACS 1971, 93, 7016. (c) Watt, D. S.; Corey, E. J. TL 1972, 4651.
3. (a) Guiseley, K. B.; Ruoff, P. M. JOC 1961, 26, 1248. (b) Smith, G. F.; Taylor, D. A. T 1973, 29, 669.

Thomas T. Tidwell

University of Toronto, Ontario, Canada



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