Acylations indium triflate

Indium triiodide catalyzes transesterification processes, e.g. the acylation of alcohols or amines and the conversion of THP ethers to acetates (Scheme 8.143) [187]. Indium triflate is also an efficient catalyst for the acylation of alcohols and amines (Scheme 8.144) [188]. Carboxylates are hydrolyzed to the corresponding carboxylic acids in high yield by microwave-assisted reaction on the surface of moistened silica gel in the presence of indium triiodide (Scheme 8.145) [189]. 

Indium(in) triflate (1 mol %) is an excellent catalyst for the Friedel-Crafts acylation reaction. The addition of 1 equiv of lithium perchlorate to the reaction mixture markedly accelerates the reaction. Thus, under mild conditions, anisole is acylated to give the product in excellent yields (eq 3). Acetic anhydride, acetyl chloride, and isopropenyl acetate can he used as acyl donors. 

Nagarajan and Perumal have demonstrated that indium(III) triflate also promotes the acylation of indoles under mild conditions and with short reaction times. Indium(III) triflate also catalyzes the reaction of indole with substituted henzaldehydes to afford his-indolyhnethanes (eq 4). 

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