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Urea‐Substituted Tetramethylcyclopentadienyl Ligands for Supramolecularly Accelerated Rh III ‐Catalyzed ortho ‐C−H Olefination of Benzoic Acid Derivatives
Author(s) -
Maurer David,
Breit Bernhard
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202005130
Subject(s) - chemistry , catalysis , benzoic acid , moiety , titration , supramolecular chemistry , urea , cyclopentadienyl complex , medicinal chemistry , substrate (aquarium) , ligand (biochemistry) , stereochemistry , organic chemistry , crystal structure , biochemistry , oceanography , receptor , geology
The design and synthesis of air‐stable and conveniently crystallizable Rh III ‐cyclopentadienyl catalysts substituted with a urea moiety, which are able to accelerate the C−H olefination of benzoic acid derivatives, is reported. Through kinetic studies and NMR titration experiments, the catalysts’ substrate recognition ability mediated by hydrogen bonding was identified to be the reason for this effect. Introduction of pyridone‐phosphine ligands capable of forming additional H‐bond interactions increased the catalytic performance even further. By unveiling a proportionality between reaction rate and relative complex formation enthalpy the hypothesis of a supramolecular catalyst preformation was supported. Its application to a variety of substrates proved the catalyst system's advantages, generally increasing the yields when compared to the results obtained with widely used [RhCp*Cl 2 ] 2 .