Indium trichloride, reaction

The use of indium in acpieous solution has been reported by Li and co-workers as a new tool in org nometallic chemistry. Recently Loh reported catalysis of the Mukaiyama-aldol reaction by indium trichloride in aqueous solution". Fie attributed the beneficial effect of water to a eg tion phenomena in connection with the high internal pressure of this solvenf This woric has been severely criticised by... 

In summary, the groups of Espenson and Loh observe catalysis of Diels-Alder reactions involving monodentate reactants by Lewis acids in water. If their observations reflect Lewis-acid catalysis, involvirg coordination and concomitant activation of the dienophile, we would conclude that Lewis-acid catalysis in water need not suffer from a limitation to chelating reactants. This conclusion contradicts our observations which have invariably stressed the importance of a chelating potential of the dienophile. Hence it was decided to investigate the effect of indium trichloride and methylrhenium trioxide under homogeneous conditions. 

Recently, solvent-free Skraup/Doebner-von Miller reactions have been developed under microwave radiation. For example, aniline 34 and enone 35 are reacted in the presence of silica gel impregnated with indium trichloride to give the corresponding quinoline 36 in good yield. It was subsequently shown that both electron-rich and electron-poor anilines undergo cyclization in a similar fashion. 

Imino Diels-Alder reactions catalyzed by indium trichloride (InCIs). Facile synthesis of quinoline and phenanthridinone derivatives [106]... 

Indium trichloride [30] and methylrhenium trioxide [31] catalyze the aqueous Diels-Alder reaction of acrolein and acrylates with cyclic and open-chain dienes. Some examples of the cycloaddition of methyl vinyl ketone with 1,3-cyclohexadiene are reported in Scheme 6.18. MeReOs does not give satisfactory yields for acroleins and methyl vinyl ketones with substituents at the jS-position and favors the self-Diels-Alder reaction of diene. 

Babu G., Perumal P. T. Synthetic Applications of Indium Trichloride Catalyzed Reactions Aldrichimica Acta 2000 33 16-22... 

Catalysts such as Fe(BuEtCHC02)3 have been d eloped that are effective for the heteroatom Diels-Alder reaction. Indium trichloride (InCls) is a good catalyst for imino-Diels-Alder reactions. Hetero-Diels-Alder reactions involving carbonyls have been done in water. Ultrasound has been used to promote the Diels-Alder reactions of 1-azadienes. ... 

Cho et al. reported a indium trichloride-catalyzed intramolecular Prins-type reactions of compounds having both the functionalities of homoallyl alcohol and acetal moiety. The intramolecular Prins cycliza-tions were performed using indium trichloride in chloroform or 25%... 

Allylation of the C-3 position of the cephem nucleus was accomplished by either indium-mediated or indium trichloride-promoted tin-mediated allylation reactions in aqueous media. Both methods gave 3-allyl-3-hydroxycephams in moderate to excellent yields.149... 

Indium trichloride349-351 is a mild Lewis acid that is effective for various kinds of Lewis-acid-catalyzed reactions such as Diels-Alder reactions (Scheme 85), aldol reactions, and Friedel Crafts reactions. Since indium trichloride is stable in water, several aqueous reactions have been investigated (Scheme 85) indium(III) triflate is also used as a Lewis acid. 

Loh, T.R, Pei, J., and Lin, M. (1996) Indium trichloride (InCl 3) catalysed Diels-Alder reaction in water. Chem. Comm. 2315-2316. 

The reaction of toluene solutions of indium trichloride and tris(trimethylsilyl)arsine resulted in the formation of a very fine dark-brown powder subsequently annealed up to 400°C to drive to completion the elimination of trimethyl-silyl-chloride. Nanocrystalline InAs was obtained. Similar reactions with InBr3 and Inl3 and P compounds have been discussed. Previously a similar reaction was described by Uchida et al. (1993) (reaction of indium acetylacetonate with tris(trimethylsilyl)arsine in refluxing triglyme). Subsequently the reaction with InCl3 was used by Guzelian et al. (1996) in the preparation of nano-crystal quantum dots. They compared different preparation methods and techniques useful to isolate specific size distributions. 

Naphthalene-based bifunctional Lewis acids that involve boron and a heavier group 13 element have also been prepared starting from the boron/tin derivative 30 (Scheme 15). Thus, the transmetalation reaction of 30 with gallium trichloride or indium trichloride in tetrahydrofuran (THF) results in high yields of l-(dichlorogallium)-8-(dimesitylboron)naphthalenediyl 35 and l-(dichloroindium)-8-(dimesitylboron)... 

Effective catalysts include TiCL,57 SnCl4,58 (CH3)3Si03SCF3,59 and Bu2Sn03SCF3.60 61 Indium trichloride catalyzes Mukaiyama additions in aqueous solution. The reaction is best conducted by preforming the aldehyde-InCl3 complex and then adding the silyl enol ether and water. 

Babu G, Perumal PT (1998) Indium trichloride (InCl3) catalyzed imino Diels-Alder reactions an efficient synthesis of cyclopentaquinolines, azabicyclooctanones and azabicyclo-nonanones. Tetrahedron 54 1627-1638... 

Crystalline indium trihalides are readily prepared from the reaction of the metal and halogen9 (sometimes in the presence of solvent), from metal+ HX, or by the electrochemical oxidation of the metal in a non-aqueous solution of X2.20 Indium trichloride and tribromide have indium octahedrally coordinated by halide in the solid state, whereas the triiodide exists as the dimer I2lnl2InI2 in the solid or in solution all three halides are dimeric in the vapor phase.9 The many adducts of these compounds with neutral donors have been extensively reviewed previously.5,7... 

The indium trichloride-catalyzed Mukaiyama aldol reaction of 3-aminoketoesters with various silylenolethers gave under solvent-free conditions 1,3-amino alcohols with high stereoselectivity [36], Several Robinson annelation reactions have been carried out enantio-selectively using (S)-proline as a chiral catalyst [37]. Remarkably, the enantioselectivity was distinctly higher in the absence of solvent than in DMSO. 

Indium trichloride-mediated addition of (i )-a-(methoxymethoxy)allylic stannane (>95% ee) to cyclohexanecarbox-aldehyde affords the anti-adduct predominantly (anti syn = 98 2) and stereoselectively (>95%ee) (Equation (12)). Production of a transient allylic indium reagent is postulated via a stereosepecific anti-Se2 transmetallation. This a-(methoxymethoxy)allylic stannane reacts without allylic inversion, whereas the reaction of crotylstannane in Equation (5) (Section 9.14.3.3.1) proceeds with net allylic inversion. <5-Oxygenated allylic stannane also undergoes transmetallation with InCl3, and in situ addition to a-ODPS acetaldehyde leads mainly to the //-adduct, which is a potential precursor to D-(+)-altrose (Scheme 31).149,150... 

The 1,2-addition of allyl iodide to cyclic and acyclic a,/ -unsaturated carbonyl compounds has been achieved by using indium and indium trichloride. The reactivities of a,/3-unsaturated carbonyl compounds depend upon their structure. The reaction of ketones smoothly undergoes in THF or DMF. In the case of cyclic ketones, however, the solvent plays a crucial role, where much improved yields have been obtained in DMF than in THF (Equation (49)).236 Indium-mediated 1,2-allylation of /3-bromoacrolein produces homoallylic alcohol derivatives (Equation (50)), which can be transformed to cyclopentanones by a Pd-catalyzed cyclization.237,238... 

Indium trichloride promotes catalytically the addition of alkynylstannanes to aldehydes (Table 25).42 Metallic indium also mediates the same Barbier-type coupling between alkynyl halides and aldehydes or ketones to give secondary or tertiary propargyl alcohols (Table 26). Secondary alcohols can be oxidized in situ according an Oppenauer process.395 Thus, alkynyl ketones have been prepared from aldehydes via an indium-mediated alkynylation reaction followed by an indium-mediated Oppenauer oxidation. They are also obtained via an indium-mediated alkynylation of the relevant acyl chlorides (Table 27).396... 

The reaction of tri- -butylindium with tetrachloroethylene affords 3-methyl- 1,1,2-trichloro-l-pentene and indium trichloride without the use of any catalyst and solvent. Other trialkylindium gives similar results (Table 29). The yield of the product based on the amount of trialkylindium used reaches 287%. This fact shows that all three alkyl groups attached to indium are effectively transferred to the product. Several haloalkenes lead to the selective formation of cross-coupling products under similar conditions. A stereospecific cross-coupling with ( )-/3-bromostyrene gives ( )-/ - -butylstyrene. In contrast, starting from both (E)- and (Z)-l,2-dichloroethylene, a mixture of (E)- and (Z)-l-chloro-3-methyl-l-pentene has been obtained in a ratio of 6 4.398... 

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