Acetoacetic ester synthesis
| Acetoacetic ester synthesis | |||||||||||
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| Reaction type | Coupling reaction | ||||||||||
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| Temperature | +Δ
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| Organic Chemistry Portal | acetoacetic-ester-synthesis | ||||||||||
| RSC ontology ID | RXNO:0000107 | ||||||||||
Acetoacetic ester synthesis is a chemical reaction where ethyl acetoacetate is alkylated at the α-carbon to both carbonyl groups and then converted into a ketone, or more specifically an α-substituted acetone. This is very similar to malonic ester synthesis.
Mechanism
A strong base deprotonates the dicarbonyl α-carbon. This carbon is preferred over the methyl carbon because the formed
Double deprotonation of ethyl acetoacetate
The classical acetoacetatic ester synthesis utilizes the 1:1 conjugate base. Ethyl acetoacetate is however diprotic:[3]
- CH3C(O)CH2CO2Et + NaH → CH3C(O)CH(Na)CO2Et + H2
- CH3C(O)CH(Na)CO2Et + BuLi → LiCH2C(O)CH(Na)CO2Et + BuH
The dianion (i.e., LiCH2C(O)CH(Na)CO2Et) adds electrophile to the terminal carbon as depicted in the following simplified form:[3]
- LiCH2C(O)CH(Na)CO2Et + RX → RCH2C(O)CH(Na)CO2Et + LiX
See also
References
- ^ Smith, Janice Gorzynski. Organic Chemistry: Second Ed. 2008. pp 905–906
- ^ Acetoacetic Ester Synthesis – Alkylation of Enolates | PharmaXChange.info
- ^ .