Theoretical studies on long-range substituent effects in the reduction of 7-norbornanones

The energetics of the stereoselective reduction of norbornan-7-one derivatives have been studied by semiempirical AM1 molecular orbital calculations, It was found that the reaction is kinetically controlled; correct prediction of the selectivity is possible only on the basis of the relative energies of the transition states of the reaction. Theoretically calculated and experimental anti-syn product ratios are in semiquantitative agreement, in contrast to results obtained from molecular electrostatic potentials. Geometry relaxation of the transition state is essential in obtaining reliable isomer ratios.