1H chemical shifts in NMR. Part 24—proton chemical shifts in some gem-difunctional compounds: 3-endo- and 3-exo-substituted norbornanones†

The complete assignment of the 1H and 13C NMR chemical shifts, from 2D techniques and spectra recorded at 500 MHz, for 3-substituted norbornanones with Cl, Br, I, SMe and SeMe substituents at endo and exo positions and 3-exo-hydroxynorbornanone is reported. The observed 1H chemical shifts are compared with the corresponding calculated values using the semi-empirical CHARGE method and ab initio calculations at the B3LYP/6–311++G(d,p) theory level. The molecular geometries were obtained through Density Functional Theory (DFT) methods. Good agreement between the experimental and both sets of calculated values is observed with the CHARGE calculations being more accurate for this series. This illustrates the utility of the CHARGE program for chemical shift assignments and also as a tool for the elucidation of chemical structures. Copyright © 2006 John Wiley & Sons, Ltd.