32785-54-9Relevant academic research and scientific papers
Oxidation of Sulfides to Sulfoxides with Hypervalent (tert-Butylperoxy)iodanes
Ochiai, Masahito,Nakanishi, Akinobu,Ito, Takao
, p. 4253 - 4259 (1997)
Oxidation of sulfides with the crystalline (alkylperoxy)iodanes, 1-(tert-butylperoxy)-1,2-benziodoxol-3(1H)-ones 2a and 2b, in acetonitrile-water or in dichloromethane, affords sulfoxides in high yields. Measurement of the relative rates of oxidation for a series of ring-substituted thioanisoles 3b (p-MeO), 3c (p-Me), and 3d (p-Cl) in acetonitrile-water indicates that electron-releasing groups such as p-MeO and p-Me groups increase the rate of oxidation, and Hammett correlation of the relative rate factors with the substituent constants affords the reaction constants ρ+ = -2.23 (σ+, r = 0.98) for BF3-catalyzed oxidation and ρ = -3.32 (σ, r = 0.98) for uncatalyzed oxidation. The effects of a free-radical scavenger, galvinoxyl, were examined. A mechanism involving the intermediary formation of the sulfonium species 11 by nucleophilic attack of sulfide toward the iodine(III) atom of 2 is proposed for the oxidation in acetonitrile-water in the presence and the absence of BF3· Et2O. On the other hand, the oxidation of sulfoxides in dichloromethane probably proceeds by a radical process, which involves the decomposition at room temperature of 2 via homolytic bond cleavage of the weak iodine(III)-peroxy bond, generating tert-butylperoxy radical and the [9-1-2] iodanyl radical 12.
