Silver benzoate iodine

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).. ... 

Iodine silver benzoate s. Silver benzoate iodine Iodine/benzoyl p eroxide s. Benzoyl peroxide/iodine Alkyl hypochlorite... 

Hydroxylation by iodine-silver benzoate (Prevost reagent)... 

Iodine silver benzoate Replacement of hydrogen by acoxy groups... 

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-... 

Thallium monoacetate, TIOCOCH3 (hygroscopic), behaves similarly to silver acetate or silver benzoate. In the presence of iodine, it accomplishes stereoselective hydroxylations of alkenes [410]. 

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). 

Stereospecific hydroxylations can also be accomplished via silver acetates [781, 782] or silver benzoates [784] and iodine followed by hydrolysis of the intermediate esters. Depending on the reaction conditions, either syn or anti hydroxylation (acyloxylation) can be accomplished (equations 78 and 79). 

In the laboratory of S. Kumar, the synthesis of phenolic derivatives of frans-7,8-dihydroxy -7,8-dihydrobenzo[a]pyrene, a highly tumorigenic compound, was accomplished. The frans-vicinal diol functionality was introduced by using the "dry" Prevost conditions. The alkene was subjected to a mixture of iodine and silver benzoate in dry refluxing benzene to give a good yield of the corresponding frans-7,8-dibenzoate derivative. 

Prevost, C., Wiemann, J. The iodinating properties of a complex iodo-silver benzoate. Compt. rend. 1937, 204, 700-701. 

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. 

The modified Prevost reaction uses bismuth acetate instead of silver benzoate. From a mechanistic point of view, iodine is considered to be the actual oxidant, and hence the bismuth acetate may work merely as the acetoxy source. Major advantages of this method over the previously reported analogous ones are as follows (i) bismuth-containing wastes are non-toxic, (ii) bismuth acetate is inexpensive, and (iii) less metal salt is needed, since three acetoxyl groups can be transferred per one bismuth atom. 

Cltaraiii of et-giycoh. Raman1 noted that the combination of silver benzoate ami iodine cleaves o-glycols to give carbonyl compounds. I.iiningand Paulsson2... 

Silver benzoate iodine Glycols from ethylene derivatives... 

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 ). 

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). ... 

---