SYNTHEIEC STUDIES TOWARDS GELSEMINE , I. THE IMPORTANCE OF THE ANTIPERIPLANAR EFFECT IN THE HIGHLY REGIOSELECTIVE REDUCTION OF NON-SYMMETRICAL CIS-HEXAHYDROPHTHALIMIDES.

Article abstract of DOI:10.1016/S0040-4020(01)87680-8

During studies aimed at the total synthesis of gelsemine an exceptional example of regioselectivity has been discovered. cis-Hexahydrophthalimides, which are non-symmetrical through the presence of the one alkyl group (see Figure 1), are reduced by sodium borohydride into the corresponding hydroxy lactams with very high regioselectivity.The corresponding cis-tetrahydrophthalimides exhibit much lower selectivity.These findings are explained on the basis of the conformational preference of the imide molecule and the antiperiplanar effect.