Acetyl hypoiodite

A considerable extension of the synthetic utility of the hypoiodite reaction is achieved if the steroid hypoiodite (2) is generated from the alcohol and acetyl hypoiodite and then decomposed in a nonpolar solvent. In this case ionic hydrogen iodide elimination in the 1,5-iodohydrin intermediate (3) is slow, thereby allowing (3) to be converted into an iodo hypoiodite (5). 

The addition of iodine electrophiles, fert-butyl hypoiodite (t-BuOI) in the presence of BF3, acetyl hypoiodite (AcOI), iodine monochloride (IC1) and iodine monobromide (IBr), to 1,3-butadiene gives always, under ionic conditions, mixtures of 1,2- and 1,4-Markovnikov adducts (equation 57). These mixtures are the kinetic products, since rearrangement to the thermodynamically stable products occurs under the appropriate conditions86. 

The acyl hypohalit reaction with iodine ob a halogen component is the well-known Prevost reaction,18i0 whioh has found some application during recent years in the field of natural prodwtB.. u. . w. In thiB ease the acyl hypoholite is acetyl hypoiodite, generated by reaction of iodine with silver nitrate in glacial acetic arid (Eq. 130). 

Of great synthetic importance is the generation of aikoxy radicals from alcohols DIB reacts first with elemental iodine to form acetyl hypoiodite which in the presence of an alcohol is converted into alkyl hypoiodite upon irradiation with visible light the aikoxy radical is generated ... 

Several related procedures for syn hydroxylation of alkenes involve a halohydrin ester (32) as the key intermediate. In Woodward s procedure an alkene in glacial acetic acid is treated with iodine and silver acetate. Acetyl hypoiodite, MeCOjI, formed by reaction of the latter two reagents attacks the alkene, R R 0=CR R in an electrophilic manner, from the less hindered side to give, by overall anti addition. 

Acetyl hypoiodite (iodine acetate), CH3COOI, is prepared by treatment of silver acetate in acetic acid with iodine at room temperature [779, 780], The reagent cleaves vicinal diols to dicarbonyl compounds [779] and degrades tertiary alcohols to ketones [780], Acetyl hypoiodite is also an intermediate in the reaction of alkenes with the so-called Simonini complex, an addition product of iodine with 2 mol of silver acetate [781, 782, 783],... 

Rather rare examples of the oxidation of tertiary alcohols are the degradation of 3-ethyl-3-pentanol to 3-pentanone and iodoethane in respective yields of 90 and 84% by acetyl hypoiodite in acetic acid and chlorobenzene under irradiation for 1 h at 20-25 °C [780 and the conversion of trflnj-9,10-dihydroxy-l,4,5,8,9,10-hexahydronaphthalene into 3,8-cyclodecadiene-l,6-dione and its tetramethylacetal by lead tetraacetate (equation 274) [447. ... 

Ogata reports iodination of aromatic compounds in fair yield by reaction with iodine and peracetic acid in acetic acid solution the effective reagent may be acetyl hypoiodite, CH3COOI. The reagent reacts with cyclohexene to give l-iodo-2-acetoxycyclohexane, but in low yield." The Provost reaction Is far better. 

The second term was ascribed to an attack of acetyl hypoiodite (CH3.CO.OI) upon phenolate ion (equations 12-13)... 

The halogenating species in the conversion of benzene to iodobenzene with iodine and peroxyacetic acid, shown in Section 12.5, is thought to be acetyl hypoiodite. Write a mechanism for the electrophilic iodination of benzene with this species. 

The combination of organic hypervalent iodine compounds, such as (diacetoxyiodo)benzene (DIB) or iodosylbenzene. Phi = O, with iodine, proposed by Suarez in the mid 1980s, was extensively used by his group for the hypoiodite reaction. As in the case of lead tetraacetate-iodine, the alkyl hypoiodites were assumed to be formed by the reaction of alcohols with acetyl hypoiodite produced in situ by the reaction of DIB with iodine at room temperature. The reaction of the alcohols with acetyl hypoiodite generates the alkyl hypoiodite (Scheme 12). The acetoxy ion is occasionally incorporated into the reaction products. 

This selenium reagent, Ph2Se(OH)OAc, was also proposed by Suarez in 1988. The reaction is carried out in cyclohexane at the reflux temperature (80°C). The active species in the formation of alkyl hypoiodites could again be acetyl hypoiodite. 

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