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Inducing Axial Chirality in a Supramolecular Catalyst
Author(s) -
Wenz Katharina Marie,
LeonhardtLutterbeck Günter,
Breit Bernhard
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201801048
Subject(s) - supramolecular chemistry , diastereomer , chemistry , chirality (physics) , circular dichroism , ligand (biochemistry) , rhodium , axial chirality , chiral ligand , stereochemistry , enantioselective synthesis , catalysis , crystallography , organic chemistry , crystal structure , biochemistry , chiral symmetry breaking , physics , receptor , quantum mechanics , nambu–jona lasinio model , quark
Abstract A new type of ligand, which is able to form axially chiral, supramolecular complexes was designed using DFT calculations. Two chiral monomers, each featuring a covalently bound chiral auxiliary, form a bidentate phosphine ligand with a twisted, hydrogen‐bonded backbone upon coordination to a transition metal center which results in two diastereomeric, tropos complexes. The ratio of the diastereomers in solution is very temperature‐ and solvent‐dependent. Rhodium and platinum complexes were analyzed through a combination of NMR studies, ESI‐MS measurements, as well as UV‐VIS and circular dichroism spectroscopy. The chiral self‐organized ligands were evaluated in the rhodium‐catalyzed asymmetric hydrogenation of α‐dehydrogenated amino acids and resulted in good conversion and high enantioselectivity. This research opens the way for new ligand designs based on stereocontrol of supramolecular assemblies through stereodirecting chiral centers.