Lexico Unisciel english version

In aqueous medium, the linear form of sugar is not stable and tends to cyclize into a more stable form : pyranose (cycle with six atoms) or furanose (cycle with five atoms). This reaction changes the hybridization state of carbon Cn1 for an aldose, of Cn2 for a 2-cetose of sp2 into sp3 making this carbon asymmetric and thus chiral. This carbon is called anomeric carbon.