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anomeric effect

Originally the thermodynamic preference for polar groups bonded to C-1 (the anomeric carbon of a glycopyranosyl derivative) to take up an axial position.
A00372-1
This effect is now considered to be a special case of a general preference (the generalized anomeric effect) for synclinal (gauche) conformations about the bond C–Y in the system X–C–Y–C where X and Y are heteroatoms having nonbonding electron pairs, commonly at least one of which is nitrogen, oxygen or fluorine. For example in chloro(methoxy)methane the anomeric effect stabilizes the synclinalconformation.
A00372-2
In alkyl glycopyranosides the anomeric effect operates at two sites (i) along the endocyclic C-1 oxygen bond (endo-anomeric effect) and (ii) along the exocyclic C-1 oxygen bond (exo-anomeric effect). The opposite preference is claimed for some systems e.g. glycopyranosyltrialkylammonium salts, and has been referred to as the reverse anomeric effect.
A00372-3
Source:
PAC, 1996, 68, 2193 (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2198
InChI=1/C6H11BrO5/c7-6-5(11)4(10)3(9)2(1-8)12-6/h2-6,8-11H,1H2/t2?,3-,4?,5-,6+/m0/s1
InChI=1/C6H11BrO5/c7-6-5(11)4(10)3(9)2(1-8)12-6/h2-6,8-11H,1H2/t2?,3-,4?,5-,6-/m0/s1
InChI=1/C7H14O6/c1-12-7-6(11)5(10)4(9)3(2-8)13-7/h3-11H,2H2,1H3/t3?,4-,5?,6-,7+/m0/s1
InChI=1/C7H14O6/c1-12-7-6(11)5(10)4(9)3(2-8)13-7/h3-11H,2H2,1H3/t3?,4-,5?,6-,7+/m0/s1
BDJLMNAHVITKNE-RONUKJSZBX
BDJLMNAHVITKNE-NIHZUXLUBI
HOVAGTYPODGVJG-CTLJMDONBA
HOVAGTYPODGVJG-CTLJMDONBA
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IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.A00372.
Original PDF version: http://www.iupac.org/goldbook/A00372.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.
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