An aldohexose is a hexose with an aldehyde group on one end.

The aldohexoses have four chiral centres for a total of 16 possible aldohexose stereoisomers (2⁴). Of these, only three occur in nature: D-glucose, D-galactose, and D-mannose. The D/L configuration is based on the orientation of the hydroxyl at position 3, and does not refer to the direction of optical activity.

There are eight D-aldohexoses:

CH=O CH=O CH=O CH=O | | | | HC-OH HO-CH HC-OH HO-CH | | | | HC-OH HC-OH HO-CH HO-CH | | | | HC-OH HC-OH HC-OH HC-OH | | | | HC-OH HC-OH HC-OH HC-OH | | | | CH2-OH CH2-OH CH2-OH CH2-OH D-Allose D-Altrose D-Glucose D-Mannose

CH=O CH=O CH=O CH=O | | | | HC-OH HO-CH HC-OH HO-CH | | | | HC-OH HC-OH HO-CH HO-CH | | | | HO-CH HO-CH HO-CH HO-CH | | | | HC-OH HC-OH HC-OH HC-OH | | | | CH2-OH CH2-OH CH2-OH CH2-OH D-Gulose D-Idose D-Galactose D-Talose

Aldehydes

Aldohexose