Iodine with silver benzoate

The same result can be achieved in one step with m-chloroperoxybenzoic acid and water.719 Overall anti addition can also be achieved by the method of Prevost. In this method the olefin is treated with iodine and silver benzoate in a 1 2 molar ratio. The initial addition is anti and results in a 3-halo benzoate (71). These can be isolated, and this represents a method of addition of IOCOPh. However, under the normal reaction conditions, the iodine is replaced by a second PhCOO group. This is a nucleophilic substitution reaction, and it operates by the neighboring-group mechanism (p. 308), so the groups are still anti ... 

Fuming or concentrated nitric acid eliminates the iodine from the di-iodide, white crystals of the b dinitrate, (CH3)2Te(N03)2, being deposited.3 These melt sharply without decomposition at 142° C. The di-iodide gives a green platinum salt with chloroplatinic acid. With silver benzoate it forms a benzoate, white needles, M.pt. 154° C., and the yellow picrate, obtained in a similar manner, crystallises... 

The syn- and anfi-diol epoxides of benz[a] anthracene and benzo[a] pyrene have been prepared from dihydroarenes by sequential Prevost reaction with silver benzoate-iodine, dehydrogenation, methanolysis, and epoxidation, e.g.,... 

A similar conversion of olefins to glycols involves reaction with iodine and silver benzoate followed by saponification of the resulting crude di-... 

Prevost method The overall //7//-hydroxylation of an alkene achieved by treating the alkene with a 1 2 molar ratio of iodine and silver benzoate, followed by hydrolysis. Overall. syw-hy droxy 1 ation may be achieved by the method of Woodward. 

Prevost reaction. Hydroxylation of olefins with iodine and silver benzoate in an anhydrous solvent to give trans-glycols. 

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). ... 

The formation of 1,2-diol products from alkenes can be achieved using Prevost s reagent - a solution of iodine in carbon tetrachloride together with an equivalent of silver(l) acetate or silver(I) benzoate. " Under anhydrous conditions, this oxidant yields directly the diacyl derivative of the anh-diol (Prdvost conditions), while in the presence of water the monoester of the syn-diol is obtained (Woodward conditions). Thus, treatment of a cw-alkene with iodine and silver benzoate in boiling carbon tetrachloride under anhydrous conditions gives the tra 5-dibenzoate (5.92). With iodine and silver(I) acetate in moist acetic acid, however, the monoacetate of the cw-1,2-dihydroxy compound is formed. 

Anti hydroxylation of an alkene is readily achieved with peroxycarboxylic adds. Add-catalyzed ring opening of the irutial produd, an oxirane (epoxide), forms the monoester of a 1,2-diol, hydrolysis of which affords the parent diol. Alternative reagents whi ate often used for anti hydroxylation of alkenes are hydrogen peroxide with oxides of tungsten > 4.2i gj. selenium, 444i and iodine-silver benzoate (Pr6vost reaction).. ... 

We may also note that acetonium or benzonium bridged ions are intermediates in the hydroxylation of olefinic bonds with iodine and silver acetate or benzoate (see p. 99). 

Benzoyl hypoiodite, C HsCOOI, a similar complex with similar applications, is formed from iodine and 2 mol of silver benzoate [783, 784], Silver p-chloro- and 3,5-dinitrobenzoates react analogously [783] (equation 17). 

A possible, alternative synthesis would be the reaction of one mole of a conduritol tetrabenzoate with one mole of silver benzoate and an excess of iodine (the Provost reaction ). 

Silver benzoate and iodine are caused to react with the alkyne in benzene or CC14 439... 

An alternative route to 1,2-diols reacts alkenes with a mixture of silver carboxylate and iodine rather than with peroxides. Prevost found that silver benzoate and iodide converted styrene to 1,2-dibenzoate 272, which could be saponified to the l,2-diol. 358 xhe transformation is called the Prevost reaction.3 6 This... 

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