Triphenyl phosphite ozonide oxidant

Reaction with aji-unsaturated ketones and lactonesThe reactivity of a,/ -enones to singlet oxygen depends on the conformation. Systems that exist in s-trans-conformations (e.g., A4-3-ketosteroids) react slowly if at all. However, s-cis-enones react readily. For example, (R)-( + )-pulegone (1) reacts to give the products 2-4. The same products are obtained by oxidation with triphenyl phosphite ozonide (3, 324 325). 

Triphenyl phosphite ozonide, (CtHsOjjPOj, which is obtained by ozonization of triphenyl phosphite in dichloromethane solution at -78 °C, decomposes to triphenyl phosphate and singlet oxygen [178]. As an oxidant, it converts the trimethylsilyl ethers of enols of a,p-unsaturated ketones into unsaturated hydroxy ketones [996]. 

Potassium permanganate. Dimethyl sulfide-Chlorine. Dimethyl sulfoxide. Dimethyl sulfoxide-Chlorine. Dimethylsulf-oxide Sulfur trioxide. Dipyridine chro-mium(VI) oxide. Iodine. Iodine-Potassium iodide. Iodine tris(trifluoroacetate). Iodosobenzene diacetate. Isoamyl nitrite. Lead tetraacetate. Manganese dioxide. Mercuric acetate. Mercuric oxide. Osmium tetroxide—Potassium chlorate. Ozone. Periodic acid. Pertrifluoroacetic acid. Potassium ferrate. Potassium ferricyanide. Potassium nitrosodisulfonate. Ruthenium tetroxide. Selenium dioxide. Silver carbonate. Silver carbonate-Celite. Silver nitrate. Silver oxide. Silver(II) oxide. Sodium hypochlorite. Sulfur trioxide. Thalli-um(III) nitrate. Thallium sulfate. Thalli-um(III) trifluoroacetate. Triphenyl phosphite ozonide. Triphenylphosphine dibromide. Trityl fluoroborate. 

Values for Polymer and Model Compounds. 1,4-Polyisoprene and 1,4-polybutadiene are so sufficiently reactive toward singlet oxygen that we can conveniently obtain / -values by three methods (a) from oxygen-uptake rates by photosensitized oxidation at different polymer concentrations (b) by the initial disappearance rate of rubrene on photooxygenation of solutions with and without polymer (or model olefin) and (c) for 1,4-polyisoprene, by the amount of rubrene consumed upon addition of aliquots of triphenyl phosphite ozonide in the presence and absence of olefin or polymer. The treatment of data from methods (b) and (c) was modified to give /3-values directly from the following equations ... 

AUylic hydroperoxides. The product ratios of the allylic hydroperoxides obtained on oxidation of alkenes with singlet oxygen differ significantly from those obtained by base-catalyzed isomerization of /3-halo hydroperoxides, which involves perepoxide intermediates. A third mechanism must be operating in the reaction of triphenyl phosphite ozonide (3, 323-324 4, 559). This last reaction presumably proceeds by an ionic mechanism, since singlet oxygen is not formed at — 70° from the ozonide. ... 

OXIDATION, REAGENTS Acetyl nitrate. Bis(tri-n-butyltin)oxide. Bromine-Hexameth-ylphosphoric triamide. f-Butyl perbenzoate. Ceric ammonium nitrate. N-chlorosuc-cinimide-Dimethyl sulfide. Chromic add. Chromic anhydride. Chromic anhydride-Acetic anhydride. Chromic anhydride-Hexamethylphosphoric triamide. 2,3-Dichloro-5,6-dicyano-l,4-benzoquinone. Dimethyl sulfoxide. Dimethyl sulfoxide-Trifluoro-acetic anhydride. Diphenylseleninlc anhydride. Iodine tris(trifluoroacetate). Lead tetraacetate. N-Methylmorpholine -N-oxide. p-NitrobenzenesulfonyI peroxide. Oxygen, singlet. Palladlumfll) chloride. Peroxybcnzimidic acid. Phenylseleninyl chloride. N-Phenyl-l,2,4-triazoline-3,5-dione. Potassium chromate. Potassium superoxide. Pyri-dinium chlorodiromate. Salcomine. Silver carbonate-Celite. Sodium hypochlorite. Sulfuryl chloridc-Silica gel. Thallium(III) acetate. ThaUium(III) nitrate. Triphenyl phosphite ozonide. Trltyl tetrafluoroborate. Uranium hexafluoride. 

Silyl enol ethers are a class of electron-rich, nonaromatic compounds that easily form reactive radical cations on one electron oxidation. The silyl enol ether functional group is closely related to the carbonyl function and consequently, syntheses of silyl enol ethers generally make use of enolates. In addition, silyl enol ethers can be described as masked enols or enolates since their reactions often yield ketones. A number of oxidation reactions of silyl enol ethers making use of oxygen or oxygen-containing reagents such as peroxides, peracids (known as Rubottom oxidation), dioxirane, osmium tetraoxide, or triphenyl phosphite ozonide have been described in the literature. In all cases either a-hydroxy-ketones or the silyl enol ether epoxides are formed. 

Iwata, C, Takemoto, Y., Nakamura, A., and Imanishi, T., Oxidation of 2-trimethylsiloxy-1,3-dienes with triphenyl phosphite ozonide. A regioselective a -hydroxylation of a,P-unsaturated ketones. Tetrahedron Lett., 26, 3227, 1985. 

Conjugated dienes (and compounds that behave like conjugated dienes in the Diels-Alder reaction) react with singlet oxygen to form cyclic peroxides as if molecular oxygen acted as a dienophile. The yields of the peroxides, prepared by photochemical oxidation [13, 55] or by chemical oxidations with hydrogen peroxide and sodium hypochlorite, alkaline hydrogen peroxide and bromine, alkaline salts of peroxy acids [14, 26], or the ozonide of triphenyl phosphite [29], are comparable. 

---