the reverse anomeric effect include an electrostatic explanation and the delocalization of the sp3 electrons of the anomeric carbon and oxygen lone pair. There is some debate as to whether or not this is a real phenomenon. The nitrogen containing substituents it has been reported with are quite bulky, making it hard to separate the normal effects of steric bulk and the reverse anomeric effect, if it does exist. For example, in the molecule shown below, the pyridinium substituent strongly prefers the equatorial position, as steric factors would predict, but actually shows a stronger preference for this conformation than predicted, suggesting the reverse anomeric effect is contributing. Metallo-anomeric effect Late transition metals from groups 10, 11, and 12 when placed at the anomeric carbon show strong axial preferences. This phenomenon termed as the metallo-anomeric effect originates from stabilizing hyperconjugative interactions between oxygen or other heteroatoms with lone pairs and C-M anti-bonding orbitals that act as good acceptors. The generalized metallo-anomeric effect refers to thermodynamic stabilization of synclinal conformers of compounds with the general formula M-CH2-OR. Axial/equatorial preferences can be influenced by ligands attached to the metal and electronic configuration. In general terms, moving from a lighter to a heavier element in the group, the magnitude of the metallo-anomeric effect increases. Furthermore, higher oxidation states favor axial/synclinal conformers. Synthetic applications The anomeric effect is taken into consideration synthetically. Due to its discovery in sugars, sugar and carbohydrate chemistry is one of the more common synthetic uses of the anomeric effect. For instance, the Koenigs-Knorr glycosidation installs an α-OR or β-OR group in high diastereoselectivity which is effected by the anomeric effect. Sophorolipid lactone, (+)-Lepicidin A, and (−)-Lithospermoside are a few of the products synthesized via the Koenigs-Knorr Glycosidation overcoming the anomeric effect. See also Alkane stereochemistry Anomer Carbohydrate conformation Conformational isomerism Cyclohexane conformation Gauche effect Intramolecular forces Monosaccharide Raymond Lemieux Steric effects References External links Carbohydrate chemistry Physical organic chemistry Carbohydrates Acetals