Skip to main content
Chemistry LibreTexts

Acetoacetic Ester Synthesis

Acetoacetic ester synthesis is a synthetic procedure used to convert a compound that has the general structural formula 1 into aketone that has the general structural formula 2.

acetoaceticestersynthesis1.png

  • R1 = alvikyl
  • L = leang group

The group —CH2COCH3 in 2 is contributed by an acetoacetic ester, hence the term acetoacetic ester synthesis.

acetoaceticestersynthesis2.png

 

  • R2 = alkyl, aryl

Acetoacetic ester synthesis consists of four consecutive reactions that can be carried out in the same pot.

  • reaction 1: acid-base reaction
  • reaction 2: nucleophilic substitution
  • reaction 3: ester hydrolysis (using saponification)
  • reaction 4: decarboxylation

eg:

acetoaceticestersynthesis3.png

reaction 1:

acetoaceticestersynthesis4.png

reaction 2:

acetoaceticestersynthesis5.png

reaction 3:

acetoaceticestersynthesis6.png

reaction 4:

acetoaceticestersynthesis7.png

A more direct method to convert 3 to 4 is the reaction of 3 with the enolate ion (5) of acetone.

acetoaceticestersynthesis8.png

However, the generation of 5 from acetone quantitatively in high yield is not an easy task because the reaction requires a very strong base, such as LDA, and must be carried out at very low temperature under strictly anhydrous conditions.

acetoaceticestersynthesis9.png

Acetoacetic ester synthesis provides a more convenient alternative to convert 3 to 4.

Acetoacetic ester synthesis can be adapted to synthesize compounds that have the general structural formula 6.
 

R3, R4 = identical or different alkyl groups

eg:

acetoaceticestersynthesis11.png

reaction 1:

acetoaceticestersynthesis12.png

reaction 2:

acetoaceticestersynthesis13.png

reaction 1 (repeat):

acetoaceticestersynthesis14.png

reaction 2 (repeat):

acetoaceticestersynthesis15.png

reaction 3:

acetoaceticestersynthesis16.png

reaction 4:

acetoaceticestersynthesis17.png