engleski

"Backdoor induction" in bioinspired asymmetric catalysis

Chiral metal complexes are used as homogeneous asymmetric catalysts very frequently. The importance of the incorporation of the chiral information as close as possible to the coordination sphere of the catalytic metal is widely accepted. In order to challenge this fundamental principle, a catalytically active metal centre that is only prochiral can be used. The chiral information is transmitted by "backdoor induction" via hydrogen bonding between distant pedant amino acids. An artificial C2-symmetrical secondary turn structure is formed that controls the chirality of the catalytic metal coordination sphere. In this communication, we present the synthesis and characterization of chiral monodentate bioconjugates L1–L3 and bidentate bioconjugates L4–L5. Rh(I) complexes with Rh(L1–L3)2 or Rh(L4–L5) stoichiometry are prepared in situ and used as catalysts in asymmetric hydrogenation of alpha, betha-dehydroamino acids with selectivity up to 81% ee. These catalysts could be models of artificial enzymes with a functional secondary coordination sphere.

amino acids; artificial metalloenzymes; asymmetric catalysis; metallated bioconjugates; supramolecular chemistry

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