InCl3: A Mild Lewis Acid but Efficient Reagent in Organic Synthesis

All articles of this category Introduction Lewis acids play a vital role in synthetic organic reactions since their use avoids the conventional, traditional and corrosive or harsh acid catalytic route. Lewis acids most habitually encountered in organic synthesis are AlCl 3 , BF 3 ·Et 2 O, ZnCl 2 , TiCl 4 and SnCl 2 . Even though indium belongs to the same group in the periodic table as boron and aluminium, InCl 3 as a Lewis acid for organic reactions has been not exploited unlike the other Lewis acids during past decades. But recently, it has been proven that InCl 3 is a mild, worthwhile Lewis acid; which is stable in aqueous medium, effectively and selectively catalyzes various important organic reactions. [ 1 ] The recent emergence of InCl 3 as an efficient Lewis acid catalyst presents new and exciting opportunities for organoindium chemistry. It has been used as a catalyst for a wide variety of organic transformations and reactions since its emergence as a catalyst. InCl 3 was used in the synthesis of aryl hydrazides, [ 2 ] 2-haloamines, [ 3 ] cis -aziridine carboxylates, [ 4 ] chiral furan diol, [ 5 ] quinolines, [ 6 ] and homoallyl acetates. [ 7 ] Also it has been used in reductive Friedel-Crafts alkyl­ation of aromatics with ketones or aldehydes, [ 8 ] for the reaction of acid chlorides with allylic tins, [ 9 ] for the insertion reactions of α-diazo ketones, [ 10 ] Biginelli reaction, [ 11 ] Mukaiyama aldol reactions, [ 1 ] imino Diels-Alder reactions, [ 1 ] in the conjugate addition of indoles with electron-deficient olefins, [ 18 ] for the bromolysis or iodolysis of α,β-epoxycarboxylic acids [ 19 ] etc.