Aldol reaction facts for kids
The aldol reaction is a very important reaction in organic chemistry. It allows to form new carbon-carbon bonds. It was discovered in 1872.
The reagents are two carbonyl compounds together with a base. A proton is removed from one of them forming a negative charge on the α-carbon (the carbon just next to the C-O double bond). The negative charge can then attack the other carbonyl compound, forming the bond. The product is a β-hydroxy carbonyl compound, a molecule with a C-O double bond and an alcohol two carbon atoms down the chain. This reaction is very powerful because it can form a big molecule from two smaller ones.
Modern ways of doing the aldol reaction also allow to control the stereochemistry of the product. This is a very good way to create new chiral centres.
Images for kids
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A typical experimental setup for an aldol reaction. The flask on the right is a solution of lithium diisopropylamide (LDA) in tetrahydrofuran (THF). The flask on the left is a solution of the lithium enolate of tert-butyl propionate (formed by addition of LDA to tert-butyl propionate). An aldehyde can then be added to the enolate flask to initiate an aldol addition reaction. Both flasks are submerged in a dry ice/acetone cooling bath (−78 °C) the temperature of which is being monitored by a thermocouple (the wire on the left).
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Stereoelectronic deprotonation requirements
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The general model of the aldol reaction with carbonyl-based stereocontrol
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Examples of the aldol reaction with carbonyl-based stereocontrol
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Aldol reaction creates stereoisomers
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Four possible stereoisomers of the aldol reaction
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Evans' chiral oxazolidinone cleavage
See also
In Spanish: Reacción aldólica para niños
