Introduction
<P>Use of magnesium(II) species as Lewis acid catalysts for various functional group
transformations is well documented.
[
1]
Of these, magnesium halides are the most useful. Ready availability and ease of preparation
prompted the frequent use of MgBr
2·OEt
2 in various organic transformations. The oxophilic and coordinating nature of MgBr
2·OEt
2 has been demonstrated through its use as a bidentate chelating Lewis acid in a number
of chelation-controlled reactions such as cycloadditions,
[
2]
asymmetric aldol reactions,
[
3]
rearrangements,
[
4]
radical additions,
[
5]
[
6]
hydrogen transfer reactions,
[
7]
stereoselective reductions,
[
8]
and anomerizations.
[
9]
</P><P>MgBr
2·OEt
2 is commercially available as a grey solid (mp >300 °C, fp 35 °C). It can be readily
prepared by reacting a slight excess of magnesium turnings with 1,2-dibromoethane
in anhydrous diethyl ether.
[
10]
The solution can be stored at room temperature for several months and the solid can
be stored in a vacuum desiccator for indefinite periods without any loss of activity.</P>
