Iodination, alcohols using applications

Iodosobenzene bistrifluoroacetate is a versatile mild oxidant that has been used to oxidize a broad range of organic compounds, such as alkenes, alkynes, carbonyl compounds, and alcohols Its application in organic synthesis has been summarized m several recent reviews devoted to polyvalent iodine compounds [63, 64, 65]... 

Section 3.2). Catalytic application of the iodine(V) species in the oxidation of alcohols has been reviewed by Uyanik and Ishihara [10, 75]. The first examples of a catalytic application of an iodine(V) species (i.e., IBX) in the oxidation of alcohols using Oxone as a stoichiometric oxidant were independently reported by the groups of Vinod [4] in 2005 and Giannis [5] in 2006. Vinod s group employed 20-40 mol% of 2-iodobenzoic acid in a water-acetonitrile biphasic solvent system, in which primary and secondary alcohols were oxidized to carboxylic acids and ketones, respectively (Scheme 4.44) [4]. 

Me3SiCH2CH=CH2i TsOH, CH3CN, 70-80°, 1-2 h, 90-95% yield. This silylating reagent is stable to moisture. Allylsilanes can be used to protect alcohols, phenols, and carboxylic acids there is no reaction with thiophenol except when CF3S03H is used as a catalyst. The method is also applicable to the formation of r-butyldimethylsilyl derivatives the silyl ether of cyclohexanol was prepared in 95% yield from allyl-/-butyldi-methylsilane. Iodine, bromine, trimethylsilyl bromide, and trimethylsilyl iodide have also been used as catalysts. Nafion-H has been shown to be an effective catalyst. 

Of the four halogens, iodine is the weakest oxidizing agent. Tincture of iodine, a 10% solution of I2 in alcohol, is sometimes used as an antiseptic. Hospitals most often use a product called povidone-iodine, a quite powerful iodine-containing antiseptic and disinfectant, which can be diluted with water to the desired strength. These applications of molecular iodine should not delude you into thinking that the solid is harmless. On the contrary, if I2(s) is allowed to remain in contact with your skin, it can cause painful bums that are slow to heal. 

Chlorine spray is used to identify peptides and amino acid derivatives. [231 A blue color is given by almost all compounds that contain NH groups. Alcohols and acids interfere with the test and should be removed prior to application of the spray. The test fails when dioxane is used to develop the plate or when certain fluorescent indicators are present. Several protocols have been described for this test.14 These protocols vary in the reagents that are used to generate the reactive chlorine and the iodine-starch reagent that is used for visualization. 

Iodine makes blue colored complexes with many substances such as starch [1, 2] nylon-6 [3], poly(vinyl pyrrolidone) [4], poly(vinyl alcohol) PVA [5, 6], From the application point of view, the blue PVA-Iodine complex is the most important among them, for it is widely used for film polarizers [7,8]. The polarizers are prepared by soaking PVA films in a solution of iodine and potassium iodide (KI) with boric acid, and subsequent drawing to cause the high... 

The title compound is produced by treatment of 2-iodylbenzoic acid with acetic anhydride in acetic acid, and has found wide application as a mild oxidant ( Dess-Martin period-inane ) for ly and 2y alcohols. Although it appears not to be sensitive to impact, unlike the precursor acid, both explode violently when heated under confinement. The oxidant, on treatment with water is hydrolysed back to the explosive 2-iodylbenzoic acid. Forethought and caution are advised before using these explosive materials on any scale of working. See 2-Iodylbenzoic acid See other IODINE COMPOUNDS, OXIDANTS... 

Although the reaction in Scheme 10 is a highly efficient procedure, a two-step process was required to prepare aziridines from olefins. Two more convenient methods for the one-step aziridination using CT were discovered by the authors in 1998, one of which involves the iodine-catalyzed aziridination of unfunctionalyzed olefins with CT trihydrate [7b] (Scheme 11). The bromine-catalyzed aziridination of unfunctionalyzed olefins and allylic alcohols with anhydrous CT was reported at the same time [7c], though in this case phenyltrimethylammonium tribromide (PTAB), and not Br2, was used as a catalyst (Scheme 12). These two reactions are applicable to a wide range of olefins, and are considered to proceed by almost the same pathway. 

Apart from their behaviour as ligands in metal catalyst systems, studies of the reactivity of phosphites towards a wide variety of other substrates have attracted attention. New aspects and applications of the classical Michaelis-Arbuzov reaction and its variants continue to appear. Evidence of the thermal disproportionation of methyltriaryloxyphosphonium halides formed in the reactions of triarylphosphites with alkyl halides, together with the formation of P-O-P intermediates, has been reported. The Michaelis-Arbuzov reaction has been used in the synthesis of phosphonate-based styrene-divinylbenzene resins and polyphosphonated chelation therapy ligands.Treatment of electron-rich benzylic alcohols dissolved in triethylphosphite with one equivalent of iodine affords a low-temperature one-pot route to the related benzylic phosphonates, compounds which are otherwise difficult to prepare. Upper-rim chloromethylated thiacalix[4]arenes have also been shown to undergo phosphonation on treatment with a phosphite ester in chloroform at room temperature. The nickel(II)-catalysed reaction of aryl halides with phosphite esters in high boiling solvents, e.g., diphenyl ether, (the Tavs reaction), has also... 

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