Enantiomeric Resolution of Asymmetric-Carbon-Free Binuclear Double-Stranded Cobalt(III) Helicates and Their Application as Catalysts in Asymmetric Reactions

Abstract

A series of double-stranded binuclear helicates [Co₂(H1)₂]⁴⁺, [Co₂(H2)₂]⁴⁺, and [Co₂(H3)₂]⁴⁺, derived from monodeprotonated bis-pyridyl hydrazine-based ligands of H₂1, H₂2, and H₂3 with one, two, and three -CH₂ spacers, were obtained. These asymmetric-carbon-free racemic helicates were separated into their ΔΔ and ΛΛ enantiomers. The resolved helicates were examined for the first time as enantioselective catalysts in asymmetric benzoylation and nitroaldol reactions.