CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

processes. Although the aspects of their toxicity and disposal have not been fully explored
yet, the use of ionic liquids can definitely make a contribution in this area, particularly with
regard to solvent and catalyst usage.
IIII. .33. .22 IInnddi iuum meeddi iaat teedd aal llyyl
laat tioonn inn i [bbmi[
im] ][Brr]
]
Indium mediated allylation of carbonyl compounds to give the corresponding
homoallylic alcohol has been extensively studied in the past two decades, 65a,73 especially
with the discovery that the reaction can be carried out in aqueous media. 64b,65b,74
As
opposed to other metals, In is less air- and moisture-sensitive, significantly less toxic, and
able to tolerate numerous functionalities offering advantages for the allylation
reactions. 64,75
In this investigation, we used In as the metal mediator and [bmim][Br] as the
solvent to develop an efficient method for allylation of aldehydes. In general, only the
hydrophobic RTILs are used for the Barbier type reactions. The simplest RTIL,
[bmim][Br] has so far been used for bromination of arylamines and α,β-unsaturated
carboxylic acids, synthesis of cyclic urethane and pyrimidinediones, 76a,b dealkylation of
aryl alkyl ethers, 76c
and most interestingly for Heck reaction. 69e However, due to its
excellent hydrophilicity, it was expected to mimic aqueous medium and appeared best
suited for the Barbier type reactions. This study also provided new mechanistic insights in
the allyl-In chemistry in [bmim][Br], eventually leading to a protocol with catalytic
quantity of In.
39