Activations indium triflate

Most of indium triflate s apphcations exploit its properties as a mild, chemoselective, and versatile Lewis acid. It has been shown to activate various functional groups containing oxygen, halogens, or carbon-carbon u--bonds, enhancing the electrophilicity or nu-cleophUicity of the complexed species. 

Boron trifluoride and indium(III) triflate were found to catalyse efficiently the isomerization of thionolactones (26) to thiolactones (27) in good yields. When applied to an optically active y-thionolactone [(/ )-28], the isomerization reaction proceeded with complete inversion of configuration to [(S)-29] by using BF3,OEt2 (Scheme 9). The proposed mechanism (Scheme 10) implicates a double S -type process involving two molecules of thionolactone, each complexed with BF3, that progresses to the product via the dimer (30).49... 

Aminoalkyl and Related Acids. - Further development of the classical three component approach to aminoalkylphosphonates (the Kabachnik-Fields reaction) has been reported. The reaction of aldehydes, hydroxylamines and dimethyltrimethylsilyl phosphite using lithium perchlorate/diethyl ether as a catalyst gives N-trimethylsilyloxy-a-aminophosphonate derivatives. The catalytic activities of various lanthanide triflates as well as indium trichloride have been examined for the Kabachnik-Fields type reactions of aldehydes, amines and the phosphorus nucleophiles HP(0)(0Et)2 and P(OEt)3 in ionic liquids. TaCb-Si02 has been utilized as an efficient Lewis acid catalyst for the coupling of carbonyl compounds, aromatic amines and diethyl phosphite to produce a-... 

Taking into account the competitive hydrolysis of the silyl enol ether, this reaction is remarkable. The method was shown to be general and was extended to a variety of aldehydes and several a,j9-unsaturated carbonyl compounds giving uniformly 1,4-addition with aldehydes and a mixture of 1,4- and 1,2-adducts in the case of ketones [187]. Later, this aqueous version of the Mukaiya-ma reaction was shown to give near quantitative yields in the presence of a water-tolerant Lewis acid such as ytterbium triflate [188]. Keeping with the same concept,copper(II) triflate [189],indium(III) trichloride [190],tris(pentafluoro-phenyl)boron [191] and scandium(III) triflate in the presence of a surfactant [192] have proved to be active catalysts. 

A novel catalyst system consisting of a palladium complex, triphenylphosphine, and indium(III) triflate is more active for the dimerization of vinylarenes compared with the generally used cationic palladium(II) catalysts (eq 22). ... 

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