THEORETICAL-STUDIES ON LONG-RANGE SUBSTITUENT EFFECTS IN THE REDUCTION OF 7-NORBORNANONES

The energetics of the stereoselective reduction of norbornan-7-one der ivatives have been studied by semiempirical AM1 molecular orbital calc ulations, It was found that the reaction is kinetically controlled; co rrect prediction of the selectivity is possible only on the basis of t he relative energies of the transition states of the reaction. Theoret ically calculated and experimental anti-syn product ratios are in semi quantitative agreement, in contrast to results obtained from molecular electrostatic potentials. Geometry relaxation of the transition state is essential in obtaining reliable isomer ratios.