Aldol reaction
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.
Aldol Reaction Media
Aldol Addition reaction equation
a typical aldol reactionFrom Eugene's version (Image:Typicalaldol.gif), stereocenters marked Dr Zak 04:07, 3 December 2006 (UTC)
A simple overview of the aldol reaction including the aldol condensation. The scheme shows both enol and enolate modes of addition.
Enolate aldol formation mechanism2
Enol aldol formation mechanism2
Zimmerman-Traxler model scheme
Crossed aldol (addition) reaction
Acidic control of the aldol (addition) reaction
Schema of the aldol reaction with two products. They are diastereomeres in syn and anti configuration.
References
- Clayden, Jonathan; Greeves, Nick; Warren, Stuart (2012). Organic Chemistry (2nd ed.). Oxford University Press. pp. 614-655. ISBN 9780199270293.