Introduction <P>Sodium methylsulfinylmethylide (sodium dimsylate, dimsylsodium), introduced by
Corey and Chaykovsky,
[
1 ]
has found widespread use
[
2 ]
in organic synthesis because of its strong basic character, nucleophilicity and its
use for the introduction of methylsulfinylmethyl group. It is conveniently prepared
1 by heating finely powered sodium hydride in an excess of anhydrous DMSO under nitrogen
at about 70 °C until hydrogen evolution stops, resulting in a clear solution. Sodium
amide can also be used as the base.
[
3 ]
</P>
<P>The reagent is highly soluble in DMSO and such solutions are sensitive to heat
and air, and decompose rapidly above 85 °C.
[
4 ]
At 20 °C they lose 8% of their activity per week. Hence, it is probably best prepared
when needed and used immediately. However, an ultrasound-mediated preparation
4 has been reported for long-time storage of the reagent. Purity can be checked by
titration with formanilide using triphenylmethane as an indicator (colorless to deep
red).
[
1 ]
</P>