Reactions of copper(II) complexes of optically active N-substituted diamines with alk-3-en-2-ones or 4-hydroxyalkan-2-ones: formation of optically active macrocycles

Abstract

The reaction of bis[(3S)-3-aminopiperidine]copper(II) with but-3-en-2-one in methanol in the presence of ammonia gives an optically active tetra-azamacrocyclic complex in ca. 80% yield. Analogous optically active complexes are also obtained from bis[(3S)-3-aminohexahydroazepine]copper(II) or bis[(2S)-2-(aminomethyl)pyrrolidine]copper(II) by the same procedure. The introduction of methyl and/or a hydroxyl group at the C⁴ position of but-3-en-2-one leads to a decrease in the reactivity of the ketones, and changes the species and distribution of the reaction products. In particular, when the C⁴ position is fully substituted with methyl groups, C–N bond formation with the secondary amino group no longer proceeds. The change in the reaction mode due to the substituents at C⁴ is discussed.