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 AlCl3, BF3·Et2O, ZnCl2, TiCl4 and SnCl2. Even though indium belongs to the same group in the periodic table as boron and aluminium, InCl3 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 InCl3 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 InCl3 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. InCl3 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.
