In organic chemistry, the anomeric effect or Edward-Lemieux effect (after J. T. Edward and Raymond Lemieux) is a stereoelectronic effect that describes the tendency of heteroatomic substituents adjacent to the heteroatom in the ring in, e.g., tetrahydropyran to prefer the axial orientation instead of the less-hindered equatorial orientation ...

2018年4月5日 · No single factor is uniquely responsible for the axial preference of a substituent that is the hallmark of the anomeric effect. A CH···G nonbonded attraction between a polar axial substituent (G) and the syn -axial hydrogen(s) in the heterocycle has …

The preference of the anomeric OH group for the axial position is called the anomeric effect, a term introduced by Lemieux in the 1960s (for the exo-anomeric effect, see Section 1.01.7.2). The anomeric effect plays an important role in carbohydrate organic synthesis.

2024年10月15日 · Discover the anomeric effect, a stereochemical phenomenon influencing carbohydrate conformation, glycosidic bond stability, and molecular recognition, with implications for organic chemistry and biochemical processes.

The anomeric effect in carbohydrate chemistry is the well-known preference for a hydroxyl substituent in the anomeric position to favor an axial orientation rather an equatorial one, despite the increased 1,3-diaxial interactions.

The anomeric effect is a phenomenon observed in cyclic carbohydrates, where the preferred orientation of a substituent on the anomeric carbon (the carbon that bears the hemiacetal or acetal oxygen) deviates from the expected orientation based on steric considerations alone.

2023年9月25日 · Anomeric effect is defined as the thermodynamic preference for polar groups bonded to C-1 (the anomeric carbon of a glucopyranosyl derivative) to take up an axial position. Since this effect is observed at anomeric carbon, therefore the name given “anomeric effect”.

2014年7月21日 · The LibreTexts libraries are Powered by NICE CXone Expert and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. We also acknowledge previous National Science Foundation support under grant …

In organic chemistry, the anomeric effect or Edward-Lemieux effect is a stereoelectronic effect that describes the tendency of heteroatomic substituents adjacent to a heteroatom within a cyclohexane ring to prefer the axial orientation instead of the less hindered equatorial orientation that would be expected from steric considerations.

2021年8月24日 · After providing the background related to the relevant types of hyperconjugation and a brief historic outline of the origins of the anomeric effect, we outline variations of its patterns and provide illustrative examples for the role of the anomeric effect in structure, stability, and spectroscopic properties.