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“Backdoor Induction” of Chirality: Trans‐1,2‐cyclohexanediamine as Key Building Block for Asymmetric Hydrogenation Catalysts
Author(s) -
Opačak Saša,
Kokan Zoran,
Glasovac Zoran,
Perić Berislav,
Kirin Srećko I.
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201801647
Subject(s) - chemistry , chirality (physics) , rhodium , substituent , denticity , selectivity , asymmetric induction , amide , catalysis , stereochemistry , metal , enantioselective synthesis , organic chemistry , quantum mechanics , nambu–jona lasinio model , quark , physics , chiral symmetry breaking
This paper describes the synthesis and characterization of 21 chiral monodentate ligands L , assembled of three building blocks utilizing amide bonds: a metal binding triphenylphosphine, a chiral cyclic diamine and an additional substituent for fine‐tuning the steric and/or electronic properties. Cis square‐planar metal complexes of Rh I and Pt II with ML 2 stoichiometry have been prepared and characterized by spectroscopic methods (NMR, IR, UV‐Vis, CD) and DFT calculations. A key feature of the metal complexes is a prochiral metal coordination sphere and “ backdoor induction ” of chirality from a distant chiral source via an outer‐coordination sphere, well‐defined by aromatic stacking and hydrogen‐bonding. The rhodium complexes were used as catalysts in asymmetric hydrogenation of α,β‐dehydroamino acids with excellent yield and selectivity (up to 97 % ee ), strongly supporting the “ backdoor induction ” hypothesis.