Stereochemical Studies. XI. Changes in the Stereochemical Courseof 1, 2-Asymmetric Induction in the Reduction of N-Substituted 2-Aminopropiophenone Derivatives with Sodium Borohydride

Abstract

Changes in the stereochemical course of 1, 2-asymmetric induction in the reduction of N-substituted 2-aminopropiophenones with sodium borohydride were examined. It was concluded that substitution for the two hydrogens of the amino group by two bulky groups is important for the synthesis of threo-isomer, while at least one of the two hydrogensof the amino group must be left attached for the synthesis of erythro-isomer. This stereochemical outcome was considered to be attributable to the steric phenomena.