SME
Organic Chemistry II · Problem type
The malonic ester synthesis in order
Use this for “Show the steps that turn diethyl malonate and 1-bromopropane into pentanoic acid.”
Put in order
Put the steps that make butanoic acid from diethyl malonate and bromoethane in order.
1
?
2
?
3
?
4
?
5
?
Assumptions
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The CH₂ between the two C=O groups of diethyl malonate is unusually acidic (pKₐ about 13), so ethoxide turns it fully into the enolate.
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The enolate’s carbon attacks the alkyl halide by SN2, so primary and methyl halides work best; tertiary ones eliminate instead.
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Acid and heat hydrolyze both esters; a carboxylic acid with C=O two carbons away loses CO₂ through a six-membered ring.
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The product is acetic acid carrying the alkyl group: R–CH₂–COOH.
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Kinetic or thermodynamic enolate
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