Preparation of Organoindium Compounds

H. Osaki and M. Oshima, Preparation of Organoindium Compounds for Manufacture of Semiconductors by MOCVD, Jpn. KokaiTokkyo Koho, JP 11012283 A2 1999. 

Procedures for the preparation of organoindium compounds from In metal with... 

K. Asakura, T. Ishihara, H. Oosaki, K. Hiromi, and S. K. Isao, Preparation of Organoindium Compounds, Jpn. Kokai Tokkyo Koho.JP 06073068, 1994. 

Preparation of Organoindium Compounds 245 Table 6.2 Reactions of aryl halides with activated indium. 

Indium(III) iodide is an important starting material for the preparation of a great variety of organoindium compounds. The synthesis described herein is a modification of a published procedure. Since the title compound is hygroscopic, a combination of Schlenk and high vacuum techniques is employed. ... 

The organoindium reagent, prepared from indium metal and bromoacetonitrile, reacts with carbonyl compounds in the presence of chlorotrimethylsilane to give /3-hydroxy nitriles (Scheme 93),336 337 Similarly, indium-mediated coupling of bromoacetonitrile or 2-bromopropionitrile with a variety of aromatic acyl cyanides affords the corresponding aromatic a-cyanoketones in moderate to good yields under mild and neutral conditions (Equation (86)).338 Carbonyl compounds are efficiently transformed into 2,2-dichloro-3-hydroxynitriles by the action of trichloroaceto-nitrile and indium(i) bromide (Scheme 94).339 Bromocyanomethylation of carbonyl compounds is also achieved by the reaction of dibromoacetonitrile and indium(i) bromide.340... 

Limited heteroleptic organoindium examples are known since they have a tendency to rearrange to form the more stable symmetrical derivatives. The preparation of the majority of the heteroleptic compounds has been investigated via (a) ligand redistribution (equation 7-8), (b) metathesis (equation 9), or (c) methane elimination (equation 10) ... 

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]. 

At room temperature In[CH2(SiMe3)]3 is a colorless pyrophoric liquid. The H NMR spectrum of the compound in benzene (reference 8 7.13) consists of two lines in area ratio 9 2, with the larger methyl line at 8 -1-0.13 and the smaller methylene line at 8 -O.OS.t The IR spectrum of the neat liquid has bands at 2935 (vs), 2885 (s,sh), 1440 (w), 1400 (w), 1350 (w), 1291 (w,sh), 1244 (vs), 920 (s), 825 (vs), 757 (vs), 720 (vs), 692 (s,sh), 580 (m), and 490 (m) cm". The compound can be used to prepare [(trimethylsilyl)methyl]indium halogen compounds by appropriate stoichiometric exchange reactions with InClj, InBrj, and Ini. Properties of many of these organoindium halogen compounds have been reported. The experimental procedure is related to that described for Al(CH2SiMe3)2Br, except that solvents are used for the reactions. 

The coordination chemistry of indium(I) received little or no attention for many years, largely no doubt because of the lack of suitable starting materials. The indium(I) halides can be easily prepared,1 but are intractable materials which readily undergo hydrolysis and disproportionation (but see Section 25.2.2.1). The only known organoindium(I) compounds are the cyclopentadienyl and methycyclopentadienyl derivatives,8 and the former has proven a useful starting point for some synthetic work. Electrochemical methods have been used either to reduce higher states, or to oxidize the metal in the presence of suitable ligands, in order to produce indium(I) species. 

Organoindium anionic compounds in which indium coordinates to both aUcyl and hydride ligands have been synthesized via the reaction of Rsin with KH (equation 32) the product, however, combines with unreacted trialkyl to give K[ (t-BuCH2)3ln 2H] (equation 33). " Complexes in which indium coordinates to both alkyl and halide ligands can be prepared by the reaction of Rsin with [NR JX (X = F, Cl,... 

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