Probing for Electronic and Steric Effects in the Peracid Oxidation of Thianthrene 5-Oxide

Abstract

A systematic examination of the electronic and steric effects in the peracid oxidation of thianthrene 5-oxide (SSO) was undertaken and has revealed valuable information on the oxidative reactivity of the SSO mechanistic probe toward peroxidic oxidants. Thus, no significant steric effect was found on the bisulfoxide (SOSO)/sulfone (SSO(2)) product ratio for aliphatic peracids with varying size of alkyl groups [R = Me, Et, i-Pr, t-Bu, (n-Bu)(Et)CHCH(2)]. However, a significant electronic effect was observed for CH(3)CO(3)H and CF(3)CO(3)H, for which the X(SO) values were 0.16 and 0.01, i.e., predominant oxidation of the sulfide functionality to the SOSO product by these oxidants. In addition, substituted perbenzoic acids displayed this trend. In contrast, the nucleophilic peracid anion led exclusively (X(SO) = 1.00) to oxidation of the sulfoxide site to the SSO(2) product. The oxygen transfer appears to be orbital-controlled since the more electrophilic oxidant is clearly the more reactive as well as more chemoselective, i.e., preferred attack at the more nucleophilic sulfide site in SSO.

New Mechanism for the Reaction of Thianthrene Cation Radical Perchlorate with tert-Butyl Peroxide

“…Our balance of products, Th and ThO is in accord with this requirement. The oxidation mechanism of ThO by dimethyldioxirane 19 or peracid 20 is analogous to the present results. They have shown that the nucleophilic oxidant such as peracid and dimethyldioxirane led exclusively to oxidation of the sulfoxide site than nucleophilic sulfide site to the SSO 2 .…”

“…Concentration factors for all products were determined with authentic materials. Thianthrene-5,10-dioxide (SOSO), 20 and thianthrene 5,5-dioxide (SSO 2 ), 20 were prepared as described in the literature. The samples were submitted to GC and GC/MS analyses.…”

Solvent Effects on the Activation Barriers of Olefin Epoxidation − A Density Functional Study

“…[6,7] Such epoxidation reactions have been extensively investigated by computational methods. [8Ϫ14] Recently we reported [15] that calculated activation barriers in the gas phase correlate in a linear fashion with the energy gap between the olefin HOMO π(CϪC) and the LUMO σ*(OϪO) of the epoxidizing peroxo group, as found previously also for epoxidation by transition metal peroxo complexes.…”

Dioxirane Oxidation of Sulfur‐Containing Organic Compounds

“…They proved that the formation of sulfone 4 cannot take place via the DMD oxidation of the sulfinyl oxygen of thianthrene 5-oxide (3) (Scheme 3). Later, Adam et al [32][33][34] reinvestigated the dioxirane oxidation of the thianthrene 5-oxide (3). The careful analysis of all the reaction products unequivocally proved that both dimethyldioxirane (1) and methyl(trifluoromethyl)dioxirane (2) are strongly electrophilic oxidants.…”