Diacetoxyiodo benzene

Diacetoxyiodo)benzene Aldrich lodobenzene diacetate Benzene, (diacetoxyiodo)-(8) Iodine, bis(aceto-0)phenyl- (9) (3240-34-4)... 

Hypervalent iodine(III) compounds, such as [bis(trifluoroacetoxy)iodo]benzene, (diacetoxyiodo)benzene and [hydroxy(tosyloxy)iodo]benzene, are commonly used as reagents in various cationic cyclizations, rearrangements and fragmentations. Numerous examples of such reactions have been reported in the literature and summarized in the reviews dedicated to synthetic applications of hypervalent iodine compounds [4,7,10,11, 180, 191, 387]. 

Delphinic acid, ml84 Dextrose, g8 Diacetone alcohol, hi50 1,2-Diacetoxyethane, el37 (Diacetoxyiodo)benzene, i24... 

Recently, one general route was proposed that involves oxidation of the starting neutral molecule by (diacetoxyiodo)benzene in the presence of strong acids. The resulting salt is highly soluble. Thus, oxidation of TTF in acetonitrile follows this scheme (Giffard et al. 2001) ... 

I, I-Bis(trif1uoroacetoxy)iodoDbenzene is prepared by dissolving, with heating, a given number of grams of (I,I-diacetoxyiodo)benzene (iodobenzene diacetate, Aldrich Chemical Company, Inc. see also Ovg. Synth., Collect. Vol. V, 1973, 660) in twice that number of milliliters of... 

Eollowing a radical process, radiation induced chain addition of allylbenzene to 1,4-dioxane 16. Efficiency of the addition depends on the concentration of the monomer <1999JRN953>. Alcohols also react, albeit in low yields (10%), with 16 in the presence of (diacetoxyiodo)benzene, probably via a radical pathway, to afford 2-alkoxy-l,4-dioxanes <2004SL2291 >. Free radicals have also been generated by decarboxylation of dimethoxydioxanecarboxylic acids 101 and added to some maleimides and acrylates with high stereoselectivity (Scheme 9) <20020L2035>. 

Numerous different mechanistic approaches have been applied for this combination. First, cyclization of phenoxy-ethanols 203, in the presence of (diacetoxyiodo)benzene and iodine, gave a mixture of 1,4-benzodioxane 13 and 6-iodo-l,4-benzodioxane 204 via alkoxy radicals (Equation 36) <1997J(P 1)787, 1996TL2441>. 

The submitters have also found that the rearrangement can be effected with (I, I-diacetoxyiodo)benzene or lodosobenzene and two equivalents of trifluoroacetic acid. 

DE0XY-2, 3,4,6-TETRA-O-ACET YL-1 - (2-CYANOETHYL)-a-D-GLUCOPYRANOSE D-GLYCERO-D-IDO-NONONONITRILE, 4.8-ANHYDR0-2,3-DIDEOXY-, 5,6,7,9-TETRAACETATE (86563-27-1 ), 65, 236 (I, I-Diacetoxyiodo)benzene, 66, 136 DIALKOXYACETYLENES, 65, 68... 

A very simple synthesis of coumestrol (228) has been described by Kappe and coworkers (Scheme 46) (74ZN(B)292). It is based upon dehydrogenation of 4-hydroxy-3-phenyl-coumarins to coumestans (720PP233). A number of 2 -hydroxy 3-phenylcoumarins were oxidized with lead tetraacetate to the corresponding coumestans 3-(l-acetoxy-4-methoxy-2-oxo-3,5-cyclohexadienyl)coumarins were obtained as by-products (76BCJ1955). Coumes-tan itself (226) has been obtained by photolysis of the phenol ether (232), which is in turn available from 4-hydroxycoumarin (229) and (diacetoxyiodo)benzene (Scheme 47) (78CB3857) via an iodonium ylide (231). 

Diacetins, gl7, gl8 Diacetone acrylamide, d568 Diacetone alcohol, hi42 Diacetonitrile, al51 (Diacetoxyiodo)benzene, i28 Diacetyl, b386... 

In contrast to the (E)-isomer, (Z)-alkenyl(phenyl)-A3-iodane 41 is labile and decomposes with a half-life time of 20 min to terminal alkynes in chloroform solution at room temperature [64]. Stereo electronically preferable reductive anti / -elimination accounts for this facile decomposition. In fact, the kinetic results for E2-type dehydrohalogenation of vinyl halides show that the relative rates of elimination decrease in the order anti /3->syn / - a-elimination [65]. Similar anti -elimination of vinyl-A3-iodane was proposed in the oxidation of methoxyallene with (diacetoxyiodo)benzene 4 to 3-acetoxy-3-methoxypropyne [66]. 

Although written usually as monomeric, Phl = 0 or PhIO, iodosylbenzene is actually polymeric, [-(Ph)I-0-]n. It is conveniently obtained upon alkaline hydrolysis of (diacetoxyiodo)benzene, as detailed in Organic Syntheses [33]. Iodosylbenzene is practically insoluble in water and is formed through the unstable intermediate PhI(OH)2 (Scheme 6). Other iodosylarenes have been obtained similarly. 

The best known member among the various classes of these iodanes is undoubtedly [hydroxy(tosyloxy)iodo]benzene (HTIB), sometimes called Koser s reagent. It is prepared readily from (diacetoxyiodo)benzene and p-toluenesul-fonic acid monohydrate in acetonitrile. The same method using p-nitroben-zenesulfonic acid or 10-camphorsulfonic acid leads to the corresponding sul-fonyloxy analogs [41,42]. Of special interest are some iodanes of this type coming from a chiral ether. Their preparation was effected by direct oxidation with sodium perborate and the isolated diacetoxy derivatives were separately treated with p-toluenesulfonic acid in acetonitrile (Scheme 8) [43]. 

It is noted that these compounds do not give stable ylides with alkali. An exception was CF3CONH2 which upon reaction with (diacetoxyiodo)benzene in methanolic KOH at -40°C afforded directly the isolable ylide PhI = NCOCF3 [3c]. 

The original method, with some slight modifications concerning purity, is still used for the preparation of [N-(p-tohienesulfonyl)iminoiodo]benzene, Phi = NTs. (Diacetoxyiodo)benzene is treated with the sulfonamide in methanolic KOH at -10 °C. The reaction mixture is poured into water and the ylide precipitates it can be recrystallized from methanol or methanol-water (4 1), although in both these solvents it undergoes partial solvolysis (Scheme 24) [69]. 

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