On the Steric Course of the Reaction of Enamines Derived from Open-Chain Aldehydes and Ketones with Nitro-olefins Yielding 2,3-Disubstituted 4-Nitroketones

Article abstract of DOI:10.1002/hlca.19850680120

The relative configuration of the nitro-ketone 12 obtained by the title reaction has been proved by a Baeyer-Villiger degradation and subsequent reduction to the amino-alcohol (+/-)-(u)-20, the relative configuration of which is identical with a sample prepared from 2-methyl-3-hydroxybutyrate of known configuration (Scheme 1).The stereochemical course of the title reaction is thus as predicted by our topological rule.It is assumed that the other nitro-ketones 13-18 described here are also formed by (lk)-combination of the trigonal centers of the educts (diastereoselectivity > 90percent, see Formulae and Fig. 1).It is not possible to reverse this relative topicity by employing (Z)-instead of (E)-components of the starting materials, due to the reversibility of the primary step of these Michael additions (Schemes 2 and 3, and Fig.2).