Journal of Organic Chemistry 2003-01-10

Enantioselective oxidation of di-tert-butyl disulfide with a vanadium catalyst: progress toward mechanism elucidation.

Suzanne A Blum, Robert G Bergman, Jonathan A Ellman

Index: J. Org. Chem. 68(1) , 150-5, (2003)

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Abstract

The mechanism of the oxidation of di-tert-butyl disulfide (1) to the chiral thiosulfinate (2) by H(2)O(2) catalyzed by bis(acetylacetonato)oxovanadium and a chiral Schiff-base ligand (3) has been investigated. Techniques included (51)V NMR spectroscopy, solvent effects on reaction enantioselectivity, and the isolation and full characterization of a 2:1 ligand-to-vanadium catalyst precursor. A model for the dramatic solvent effect on the enantioselectivity of this reaction was developed, based on the identification of a competing nonselective oxidation pathway. From this model, strategies for limiting this competing pathway were developed.