Introduction <P>Diethyl azodicarboxylate (DEAD) and diisopropyl azodicarboxylate
(DIAD) (Figure
[
¹ ]
),
are widely used reagents in organic synthesis. </P>
Figure 1
<P>These are important reagents in the Mitsunobu reaction,
[
¹ ]
[
² ]
which
is a versatile and widely used method for the dehydrative coupling
of an alcohol with clean stereogenic inversion and is perhaps the
most favorable reaction to invert chiral centers of secondary alcohols.
[
¹ ]
[
² ]
This
kind of reaction can also be applied in aminations, cyclodehydrations,
deoxygenations, and in dehydrative alkylations.
[
³ ]
</P><P>Besides the direct association of DEAD/DIAD with the Mitsunobu
reaction,
[
² ]
there are many
other reactions in which these reagents can be applied. For example,
DEAD/DIAD are efficient components in Diels-Alder
reactions and in click chemistry,
[
4a ]
they
function as dienophiles in some cycloadditions,
[
4b ]
and they can be used in the synthesis
of functionalized β-amino alcohols from aldehydes and ketones.
[
4c ]
DEAD and DIAD are commercially
available or can be prepared in the laboratory in a two-step synthesis
from hydrazine, first by condensation with ethyl chloroformate followed
by treatment of the resulting ethyl hydrazodicarboxylate with chlorine
or fuming nitric acid (Scheme
[
¹ ]
).
[
5 ]
</P>
Scheme 1
