Osmium tetroxide silver chlorate

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. 

Hydroxylation Boric acid (see Diborane). Hydrogen peroxide. Hydrogen peroxide-Osmium tetroxide. Hydrogen peroxide-Selenium dioxide. Osmium tetroxide. Osmium tetroxide-Barium chlorate. Peracetic acid. Perbenroic acid. Persucdnic acid. Pertrifluoroacetic acid. Potassium permanganate. Potassium persulfate. Selenium dioxide. Silver acetate. Silver chlorate. 

Hydroxylation Lead tetra(trifluoroacetate). Osmium tetroxide. Silver acetate-iodine. Silver chlorate. 

Syn-Dihydroxylation. When the reaction was first discovered, the syn-dihydroxylation of alkenes was carried out by using a stoichiometric amount of osmium tetroxide in dry organic solvent.56 Hoffman made the observation that alkenes could react with chlorate salts as the primary oxidants together with a catalytic quantity of osmium tetroxide, yielding syn-vicinal diols (Eq. 3.11). This catalytic reaction is usually carried out in an aqueous and tetrahydrofuran solvent mixture, and silver or barium chlorate generally give better yields.57... 

Osmium tetroxide is also a catalyst in the oxidation of the double bond by chlorates. Cis addition of hydroxyl groups takes place as is shown by the preparation of cis-l,2-cyclohexanediol from cyclohexene and the formation of the proper diastereoisomeric dihydroxy derivatives of maleic, fumaric, and 4-halocrotonic acids. Silver chlorate is preferred to potassium chlorate in the hydroxylation of crotonic acid. ... 

Sodium chlorate, NaC103 potassium chlorate, KCI03 silver chlorate, AgCIOj and barium chlorate, Ba(CIOj)2, oxidize organic compounds only in the presence of catalysts, usually osmium tetroxide [310, 714, 715, 716, 718] or vanadium pentoxide [716, 718]. Because such oxidations do not occur without catalysts, it is likely that the real oxidants are osmium tetroxide and vanadium pentoxide, respectively, and that the function of the chlorates is reoxidation. 

Hydroxylation at double bonds of unsaturated carboxylic acids is accomplished stereoselectively by the same reagents as those used to hy-droxylate alkenes. syn Hydroxylation is carried out with potassium permanganate [101] or osmium tetroxide with hydrogen peroxide [130], sodium chlorate [310, 715], potassium chlorate [715], or silver chlorate [310] as reoxidant, anti Hydroxylation is achieved with peroxyacids, such as peroxybenzoic acid [310] or peroxyformic acid, prepared in situ from hydrogen peroxide and formic acid [101] (equation 472). 

Posternak prepared five ortlio-tetrol diastereoisomers (54, 55, 56, 60, and 61) by the appropriate cis or trans hydroxylation of ds- or trans-S-cyclohexene-l,2-diol (58 or 59). cis-Hydroxylation may be effected with permanganate or with silver chlorate-osmium tetroxide Imns-hydroxy-lation with a peroxy acid, or with silver benzoate-iodine (the Provost reagent). ... 

Sable and coworkers also synthesized all four of the predicted racemic forms of cyclopentanetetrol (131-134), and the meso diastereomer (130). The all-cfs, meso isomer is unknown. cis-Hydroxylation of the enediols (136 and 137) is effected with permanganate or with silver chlorate-osmium tetroxide Irans-hydroxylation is caused by peroxybenzoic acid. Ihe epoxy group enters ds to the neighboring, free hydroxyl group in the intermediates (136-A, 136-B, and 137-A), according to Henbest s rule. However, prior reaction of the diol structure in the intermediate (136-A) with acetone caused the epoxide group to enter trana,... 

Olefins can be oxidized stereospecifically to cz,y-a>glycols by aqueous potassium chlorate solutions118 or, better, silver chlorate solutions119 if a little osmium tetroxide is added (Hofmann). The method is suitable mainly for conversion of water-soluble olefins into glycols and cannot be used for water-insoluble olefins.120,121... 

Other epoxidizing reagents which have been proposed but have not been extensively employed with olefinic acids include r-butyl hydroperoxide and transition metal salts, hydrogen peroxide and isocyanate, sodium chlorate and osmium tetroxide, iodine and silver oxide and hydrogen peroxide and ortho esters. 

P-DL-ribopyranoside from furfuryl alcohol have been described. cis-Hydroxyl-ation of the enones (4) and (5) with silver chlorate-osmium tetroxide gave methyl... 

The lactone derivatives (369) prepared from L-glutamic acid (2-amino-2,3,4-trideoxy-L- /ycero-pentaric acid) can be converted into the 5,5-di-C-methylpent-ose derivative (370) by the reactions outlined in Scheme 65. A salient feature of the synthesis is that the chirality of L-glutamic acid is preserved at C-2 of (370). The enone (371) [prepared from 2-(2-furyl)propan-2-ol] has been converted into methyl 2,3-0-isopropylidene-5,5-di-C-methyl-P-DL-ribopyranoside (372) by cis-dihydroxylation (silver chlorate-osmium tetroxide) and stereoselective reduction (lithium aluminium hydride) of the 2,3-0-isopropylidene derivative of the resulting diol. ... 

Osmium tetroxide in dry organic solvent was subsequently used for syn-dihydroxylations of alkenes. In fact, only a catalytic amount of osmium tetraoxide was needed the reaction was done in presence of chlorate salt as primary oxidant. The reaction is normally carried out in water-tetrahydrofuran solvent mixture (Scheme 69). Silver or barium chlorate gave better yields. 

DL-Mannitol (a-acritol) has been obtained by the reduction of a-acrose (see p. 104). Divinylglycol from acrolein was the starting point of Lespieau and Wiemann (4S). The glycol was obtained from acrolein by reduction with the zinc-copper couple and was then oxidized with silver chlorate and osmium tetroxide to DL-mannitol. Allitol was obtained simultaneously. It is apparent, therefore, that this divinylglycol must be a mixture of diols in which the hydroxyls are cis and trans. 

The combination of A -bromoacetamidc, silver acetate, and dry acetic acid has been shown to be superior to Woodward s procedure for the rfy-hydroxylation of olefins. Work up of the reaction mixture is simply effected by hydrolysis of the dioxolenium ion, followed by cleavage of the hydroxyacetate intermediate with lithium aluminium hydride. The use of a co-oxidant, such as sodium chlorate or hydrogen peroxide, allows the addition of catalytic quantities of osmium tetroxide to prepare c/y-diols from olefins. However the reaction is often complicated by further oxidation of the glycol to the a-ketol. The use of tertiary amine A -oxides, particularly A -methylmorpholine A -oxide, prevents this oxidation and gives higher yields of the desired product (Table 6). Another variation on this theme employs... 

---