Chemistry Reference
In-Depth Information
This is an acid-base proton exchange between lithium diisopropylamide (LDA, pK
a
of diisopropylamine is approximately 35) and methyl acetoacetate (pK
a
is approxi-
mately 12). Please note the transfer of the lithium counter ion from LDA to the depro-
tonated methyl acetoacetate.
This is a direct S
N
2 displacement of the bromide anion of tert-butyl bromoacetate by
a methyl acetoacetate anion. Lithium bromide (LiBr), the salt by-product, is not
shown in the reaction below.
The first step of this reaction is an acid-base proton exchange between a hydroxide
anion (pK
a
of water is approximately 16) and a primary alcohol (pK
a
is approxi-
mately 16) forming the illustrated alkoxide, B. Formation of water, the by-product,
is not shown in this step.
The second step of this reaction is a direct S
N
2 displacement of a bromide anion by
the alkoxide anion present in the same molecule. This step leads to formation of
