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Picolinamides as Effective Ligands for Copper‐Catalysed Aryl Ether Formation: Structure–Activity Relationships, Substrate Scope and Mechanistic Investigations
Author(s) -
Sambiagio Carlo,
Munday Rachel H.,
Marsden Stephen P.,
Blacker A. John,
McGowan Patrick C.
Publication year - 2014
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.201404275
Subject(s) - chemistry , aryl , ether , combinatorial chemistry , amide , ligand (biochemistry) , picolinic acid , copper , denticity , substrate (aquarium) , redox , coupling reaction , organic chemistry , metal , catalysis , receptor , biochemistry , alkyl , oceanography , geology
Abstract The use of picolinic acid amide derivatives as an effective family of bidentate ligands for copper‐catalysed aryl ether synthesis is reported. A fluorine‐substituted ligand gave good results in the synthesis of a wide range of aryl ethers. Even bulky phenols, known to be very challenging substrates, were shown to react with aryl iodides with excellent yields using these ligands. At the end of the reaction, the first examples of end‐of‐life Cu species were isolated and identified as Cu II complexes with several of the anionic ligands tested. A preliminary mechanistic investigation is reported that suggests that the substituents on the ligands might have a crucial role in determining the redox properties of the metal centre and, consequently, its efficacy in the coupling process. An understanding of these effects is important for the development of new efficient and tunable ligands for copper‐based chemistry.