Lactol
In organic chemistry, a lactol is the cyclic equivalent of a hemiacetal or a hemiketal. The compound is formed by the intramolecular nucleophilic addition of a hydroxyl group to the carbonyl group of an aldehyde or a ketone.[1]
The lactol functional group, highlighted in blue, is present in many sugars such as ribose shown here.
A lactol is often found as an equilibrium mixture with the corresponding hydroxyaldehyde. The equilibrium can favor either direction depending on ring size and other conformational effects.
The lactol functional group is prevalent in nature as component of aldose sugars.
Chemical reactivity
Lactols can participate in a variety of chemical reactions including:[2]
- Oxidation to form lactones
- Reaction with alcohols to form acetals
- The reaction of sugars with alcohols or other nucleophiles leads to the formation of glycosides
- Reduction (deoxygenation) to form cyclic ethers
References
- IUPAC Gold Book lactols
- Lundt, Inge (2001). "Oxidation, reduction and deoxygenation of carbohydrates". Glycoscience (1): 501–531.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.