Beilstein J. Org. Chem.2019,15, 818–829, doi:10.3762/bjoc.15.79
halogen size. Instead, the equilibrium is influenced by solute–solvent hydrogen bonding with the hydroxy group.
Besides the classicaleffects, interactions such as hyperconjugation has been pointed out as relevant in several studies involving cyclohexane derivatives [4][12][15][16][17][18][19][20]. Since
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Graphical Abstract
Figure 1:
Conformations of cis-2-halocyclohexylamines, where X = F, Cl, Br and I.
Beilstein J. Org. Chem.2017,13, 1781–1787, doi:10.3762/bjoc.13.172
bonding, hyperconjugation, electrostatic and steric effects. While the gauche effect, originated from hyperconjugative interactions, does not appear to cause some preferences for the axial conformation of organofluorine heterocycles, more classicaleffects indeed rule the conformational equilibrium of the
compounds. Spectroscopic parameters (NMR chemical shifts and coupling constants), which can be useful to determine the stereochemistry and the interactions operating in the series of 2-fluorocyclohexanone derivatives, were also calculated.
Keywords: classicaleffects; conformational analysis; 2
hydrogen bonding, when possible, is a better source of stabilization, but the interaction of F with Y (or the C=Y bond) appears to be more relevant as the controlling effect of the conformational isomerism of the studied compounds. Thus, classicaleffects explain satisfactorily the conformational behavior
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Graphical Abstract
Figure 1:
2-Fluorocyclohexanone (X = CH2 and Y = O) derivatives (X and Y = CH2, NH, O or S).