The ano meric effect in Į-halo-O-oxime ethers; effects of different substitutio ns with different electronic p roperties

The a nomeric eff ect explains the preferen ce of the g auche conformer over t he anti conf ormer in an R–Y–CH۲– (Y=O, N o r S; X=O, N , halogen, e tc) fragment [۱]. One e xplanation for the validit y of the anomeric effect is hyperc onjugation model, in which the overlap between a nonbonding electron pair on the Y atom and the vacant ı* orbital of the C–X bond is respon sible for th e anomeric e ffect [۲]. T hus the hyperconjugation causes stre ngthening the Y-C bon d and wea kening the C-X bond. I nvestigatio n the influences of vari ous substit utions (with different electronic properties such as electro n-withdrawing and electron-donatin g) in differ ent oxime p ositions (R۱ and R۲ positions, see Fig. ۱) on the anomeric effect in Į-c hloro-O-oxime ethers ( ACOEs, as representative for their halo-substituted analogues) is the purpose of this paper. Various parameters associated with the anomeric effect have been analyzed.

کلیدواژه ها:

anomeric effect ، Į -halo-O-oxime ether ، s ubstitution effect ، DFT ، NBO