Dioxiranes: a new class of powerful oxidants

Abstract

Ace. Chem. Res. 1989,22, 205-211 205 unenriched while the cis-trans isomer and 10 must be enriched. This was confirmed for 612. Photolysis at 10 "C of cis-612 gives p = 0, 90, 128% (130%) for cis-612, trans-(i12, and lol2, respectively, whereas photolysis of t r~n s -6 ,~ gives ( 3 = 68, 2, 131% for the same three compound^.^^ This confirmation strongly supports the above model.In summary, the physical basis for the difference in 13C enrichment among the products of biradical decay is the inherent tendency of HFC and SOC to produce different products, and this in turn comes from the R dependences of the different ISC mechanisms shown in Figure 2.Conclusion. Through a combination of product studies, isotope effects, and transient absorption kinetics including the effect of biradical chain length and substituent, solvent, temperature, and magnetic field, we have made progress in elucidating the relation of the rates and product distributions to the spin interactions in the biradicals. Probably the most surprising result is the profound effect exerted by extremely small interactions such as the S-T gap, SOC, and HFC upon the dynamics and product distribution of triplet biradicals.

Highly enantioselective epoxidation of styrenes: Implication of an electronic effect on the competition between spiro and planar transition states

“…52-56, 62, 68, 69, 89, 90, and 101-107). The primary frontier orbital interaction for both spiro and planar approaches is between the highest occupied molecular orbital of the alkene ( of CAC) and the lowest unoccupied molecular orbital of the dioxirane (* of OOO), which accounts for the electrophilic nature of the dioxirane (52)(53)(54). Both experimental and theoretical studies show that, in general, spiro transition states are favored over planar transition states (52-56, 62, 68, 69, 89, 90, 101-107).…”

“…[52][53][54]. Chiral dioxiranes were shown recently to be effective for asymmetric epoxidation of trans-, trisubstituted , and certain cis-alkenes (92)(93)(94)(95).…”

Modification of olefinic double bonds of unsaturated fatty acids and other vegetable oil derivatives via epoxidation: A review

“…This reagent is not commercially available due to instability during transport and storage but it can be prepared by reacting acetone and the triple salt Oxone ® (2KHSO 5 ·KHSO 4 ·K 2 SO 4 ) in the laboratory, both on small and large scales (Adam et al, 1987). Adam et al (1989) suggested that pH control between 7.0 and 7.5 by means of phosphate or bicarbonate buffer is essential for in-situ generation of dioxirane as low pH will suppress the critical deprotonation step (from 2 to 3, Scheme 5). In addition, high pH leading to the destruction of dioxirane by oxygen transfer competition from the dioxirane to the substrate or SO 4 2-, and autodecomposition .…”

Dioxirane oxidation of sulfur-containing organic compounds

“…Early synthetic applications of these oxidants were restricted to in situ generated dioxiranes. A real milestone for the utilization of dioxiranes in synthetic organic chemistry was the preparation of isolated dimethyldioxirane (DMD) (1) …”