SME
Organic Chemistry II · Problem type
The aldol reaction in order
Use this for “Show the steps by which propanal and NaOH give 3-hydroxy-2-methylpentanal, then an enal on heating.”
Put in order
Put the steps of the aldol reaction of ethanal with NaOH in order.
1
?
2
?
3
?
4
?
Assumptions
•
An α hydrogen sits on the carbon next to the C=O; the C=O pulls on it, so a base such as HO⁻ can remove it.
•
The enolate’s negative charge is shared by the α carbon and the O; the carbon end makes the new C–C bond.
•
Heating the aldol with base removes water across the α and β carbons, giving a C=C conjugated with the C=O.
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