Indium metal/iodide

Indium metal reduces the pyridine ring in quinoline in aqueou sethanol solution.Samarium iodide (Sml2) reduces pyridine in aqueous THF ° and phenol in MeOH/KOH. ... 

The zinc-mediated Reformatsky reaction is one of the classical methods for carbon-carbon bond formation. To date, various main group metals and transition metals have been used for this reaction. Rieke s activated indium powder mediates readily the coupling of ethyl a-bromoacetate and a variety of carbonyl compounds yielding /3-hydroxy esters in good yields (Scheme 87).3 Later, commercially available indium powder has been found to be equally effective for the indium-based Reformatsky reaction in THF.28 This indium Reformatsky reaction is accelerated by ultrasound irradiation (Scheme 88).322,323 Indium(i) iodide also mediates the Reformatsky reaction of aldehydes and ketones to give /3-hydroxy esters, presumably via organoindium(m) diiodide (Scheme 89).27... 

Reaction of phenacyl iodide with indium metal gives 3,4-epoxy-1,3-diphenyl-1-butanone which, on treatment with silica gel, gives 2,4-diphenylfuran and 2,4-diphenyl-4-oxobutanal (Scheme 92). Metallic indium as well as indium(i) iodide mediate the aldol condensation between ce-halo ketone and aldehyde.333... 

Indium metal in water reduces a-halocarbonyl compounds and benzyl iodides to the corresponding dehalogenated products in excellent yields under sonication, though simple alkyl and aryl iodides remain inert under these conditions (Equation (97)).379 Similar dehalogenation in micellar systems in the presence of a catalytic amount of sodium dodecyl sulfate in water affords the corresponding parent carbonyl compounds in excellent yields (Equation (98)).380 The allylic iodide or acetate is reduced by indium into the corresponding 3-methylcephems and 3-methylenecephams in an aqueous system. The latter are converted into the former quantitatively under basic conditions (Scheme 110).381... 

Vinyl halides add to allylic amines in the presence of Ni(cod)2 where cod=l, 5-cyclooctodine, followed by reduction with sodium borohydride. Aryl iodides add to alkynes using a platinum complex in conjunction with a palladium catalyst. A palladium catalyst has been used alone for the same purpose, and the intramolecular addition of a arene to an aUcene was accomplished with a palladium or a GaCl3 catalyst, " AUcyl iodides add intramolecularly to aUcenes with a titanium catalyst, or to alkynes using indium metal and additives. The latter cyclization of aryl iodides to alkenes was accomplished with indium and iodine or with Sml2. " ... 

Transesterification. Indium(III) iodide is prepared in situ from indium metal slices and iodine in dry isopropanol at ambient temperature for 0.5 h. Methyl esters are converted to isopropyl esters by the solution. 

It has also been reported that C6F5I will react with indium metal.70 More recently Gynane, Waterworth and Warrall71 reported the successful reaction of methyl, ethyl, and propyl bromides and iodides with metallic indium. The reaction, however, was very slow requiring 1—3 days for the iodides and 3-5 days for the bromides. Also, they found that the product was a mixture of R2InX and RlnX2. 

In the past decade much effort in organoindium chemistry has been devoted to study of carbonyl allylation and aUylindation of carbon-carbon multiple bonds with allylic indium reagents. Apart from the conventional transmetalation of allyl-lifhium or aUyl Grignard reagents with indium(III) halides, a method widely used for preparation of allyhndium(III) compounds is the oxidative addition of metallic indium or indium(I) iodide to aUyhc substrates [3, 6]. Transmetalation of allylstan-nane with indium(III) chloride also gives allylindium(III) [7]. Allylindium(I) was recently prepared by transmetalation of allylmercury with metallic indium in water this compound is regarded as an intermediate in the allylation of carbonyl compounds in aqueous media [8]. A new method of preparation of allylic in-dium(III) reagents - reductive transmetalation of a 7r-allylpalladium(ll) complex with indium(I) salts has been reported this enables the use of a wide variety of allylic compounds and solvents [9]. 

Naito described the use of indium metal to initiate a radical addition/cyclization cascade in aqueous media. Stirring a mixture of isopropyl iodide, 453, and indium powder in water at 20 °C for 2h produced lactam 454 in 63% yield as a 3 l-mixture of trans- and (Tv-isomers (02OL3835). The reaction of sulfonamide 455 under similar conditions led to the isolation of sultam 456 as a 1 1.5-mixture of isomers in 81% yield. 

Activated indium metal reacts with aryl iodides to give a good yield of diphenyl- or ditolyl-indium iodides. ... 

Indium Phosphide. InP mo] wt 145.80. In 78.75%, P 21.25%. Prepd from white phosphorus and indium iodide at 400" Tbiel, Koelsch, X. Anorg. Chem. 66, 319 (1910) from phosphorus vapor and heated indium metal Jandelli, Gaze. Chirn. Ital. 71, 58 (1941). Synthesis in zone melting furnace at 1010° from a non-stoichiometric melt Minden, Syfvonki Technologist 11, no. 1, 18 (Jan 1958). 

Note that there are several modern versions of the Barbier reaction that use transition metals or their derivatives.Examples include indium metal, samarium iodide, and lead. An example using lead reacted benzaldehyde with allyl bromide in the presence of lead metal to give a 99% yield of 45.56 A retro-Barbier fragmentation has also been reported in which an alcohol was treated with 10 equivalents of bromine and 15 equivalents of potassium carbonate in chloroform to give a bromo ketone.5 ... 

The procedure described below for the preparation of indium(I) bromide is extremely simple. Moreover, by appropriate variation of the stoichiometry of the reactants, it can be used for the preparation of indium dibromide. The preparation consists of the reaction of indium metal with mercury(II) bromide at an elevated temperature in a sealed evacuated tube. Mercury (I) bromide can be used in place of the mercury(II) compound. The same method can also be used for the synthesis of the chlorides and iodides of lower-valent indium. ... 

Indium metal or indium iodide as a reducing agent can be used for umpol-ung of TT-allylpalladium. Araki reported that allylic indium(III) reagents 333 are generated in situ by reductive transmetallation of r-allylpalladium with indium(I) salts [124]. Based on this reaction, nucleophilic allylation of benzaldehyde with allylic chlorides, alcohols, and esters occurred at room temperature in the presence... 

Little work has been reported concerning the direct synthesis of alkylindium halides. Gynane and coworkers [2] reported the direct reaction of indium metal with alkyl halides. The reaction times were, however, on the order of a day or more, and the product was a mixture of R2lnX and RI11X2. We have found that our reactive indium will react with methyl and ethyl iodide in 2h at 80°C in xylene to give nearly quantitative yields of a single product, the dialkylindium iodide. The overall reaction scheme is summarized as follows ... 

This black indium powder was found to react rapidly with aryl iodides. For example, the activated indium reacted with neat iodobenzenes at 150°C, and in 2 h over 94% yield of diphenylindium iodide was obtained. For comparison, the same reaction was run with commercial indium powder (atomized, 325 mesh) and yielded only 30% diphenylindium iodide after 25 h. It is interesting to note that considerable conglomeration of the indium metal particles occurred with the commercial indium powder. It is felt that this conglomeration is, to a large extent, responsible for the low reactivity of the commercial indium metal. Attempts to prevent the conglomeration by the addition of potassium chloride failed. 

Recently Deacon and Parrott [12] reported the direct reaction of indium metal with iodopentafluorobenzene. The reaction yield was <40%, and the product composition was dependent upon the stoichiometric ratios of reactants trispentafluorophenylindium was prepared with an excess of indium metal but was mixed with bispentafluorophenylindium when the stoichiometric amount was used. We have found that our indium will react with neat iodobenzenes or iodotoluene at 150°C for 2h to give a very high yield, 94% and 93%, respectively, and only a single product. The diphenylindium iodide or ditolylindium iodide is formed regardless of the stoichiometric ratios of reactants. The reactions of aryl halide with activated indium powder at various... 

Another example is indium(0)-induced electron transfer to aziridines 270 incorporating allyl iodide moieties (Scheme 2.66). Treatment with indium(O) in MeOH at reflux gave the corresponding chiral (E)-dienylamines 271 in excellent yields [98]. It should be noted that indium was found to be more effective for this transformation than other metals such as zinc, samarium, and yttrium. 

Allenyl iodides can be prepared from propargylic mesylates by Sn2 displacement with LiCuI2 (Eq. 9.143) [118]. The reaction proceeds primarily by an anti pathway with slight racemization. Metallation of these iodides with powdered indium in various donating solvents leads to transient allenylindium intermediates which react in situ with aldehydes to afford anti homopropargylic alcohols (Table 9.52). Additions... 

The effect of metal promoter species on the rate of carbonylation of [Ir(CO)2l3Me] was tested. Neutral ruthenium iodocarbonyl complexes such as [Ru(CO)3l2]2> [Ru(CO)4l2] or [Ru(CO)2l2]n were found to give substantial rate enhancements (by factors of 15-20 for a Ru Ir ratio of 1 13 at 93 °C, PhCl). Indium and gallium triiodides and zinc diiodide had comparable promotional effects. By contrast, addition of anionic ruthenium(II) species [Ru(CO)3I3] or [Ru(CO)2I4]2 did not lead to any appreciable promotion or inhibition. This behaviour indicates that the ability to accept an iodide ligand is a key property of the promoter. Indeed, it has been demonstrated that an iodide ligand can be transferred from [ Ir(C0)2l3Me] to neutral ruthenium or indium species [73,74],... 

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