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Enders SAMP/RAMP hydrazone-alkylation reaction
The
Enders SAMP/RAMP hydrazone alkylation reaction
is an
asymmetric
carbon-carbon
bond
formation reaction facilitated by
pyrrolidine
chiral auxiliaries
. It was pioneered by
E. J. Corey
and
D. Enders
in 1976, and was further developed by
D. Enders
and his group. This method is usually a three-step sequence. The first step is to form the
hydrazone
between (
S
)-1-amino-2-methoxymethylpyrrolidine (
SAMP
) or (
R
)-1-amino-2-methoxymethylpyrrolidine (
RAMP
) and a
ketone
or
aldehyde
. Afterwards, the hydrazone is
deprotonated
by
lithium diisopropylamide
(
LDA
) to form an
azaenolate
, which reacts with
alkyl halides
or other suitable
electrophiles
to give
alkylated
hydrazone species with the simultaneous generation of a new
chiral center
. Finally, the alkylated ketone or aldehyde can be regenerated by
ozonolysis
or
hydrolysis
.
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