Experimental and theoretical investigation of NMR 2JHH coupling constant on six-membered ring systems containing oxygen or sulfur atoms

Theoretical and experimental (2)J(HH) coupling constants for six-membered rings containing oxygen or sulfur atoms were studied to investigate whether the (2)J(HH) coupling constant can be used for stereoelectronic studies in heterocyclohexanes, instead of (1)J(CH), because it is well known that experimental measurements of (2)J(HH) coupling constants at low temperature are much easier to determine than the corresponding (1)J(CH) couplings. For all compounds studied here, the (2)J(HH) coupling constants are affected by sigma*(C-H) antibonding occupancy together with bond angle effects. For cyclohexane and oxygen-containing compounds, the influence on the geminal coupling for H-ax-C-2-H-eq and for X-l-C-2-X-3 (X = O and C), bond angles are more pronounced than for the sulfur derivatives. Copyright (c) 2007 John Wiley & Sons, Ltd.