6508-04-9Relevant articles and documents
Diaryl Ether Formation Merging Photoredox and Nickel Catalysis
Liu, Le,Nevado, Cristina
supporting information, p. 2188 - 2193 (2021/05/04)
Photoredox and Ni catalysis are combined to produce diaryl ethers under mild conditions. A broad range of aryl halides and phenol derivatives are cross-coupled in the presence of a readily available organic photocatalyst and NiBr2(dtbpy). Symmetrical diaryl ethers have also been directly obtained from aryl bromides in the presence of water. Mechanistic investigations support the involvement of Ni(0) species at the outset of the reaction and a Ni(II)/Ni(III)-photocatalyzed single electron transfer process preceding the productive C(sp2)-OAr reductive elimination.
The Delicate Balance of Preorganisation and Adaptability in Multiply Bonded Host–Guest Complexes
von Krbek, Larissa K. S.,Achazi, Andreas J.,Schoder, Stefan,Gaedke, Marius,Biberger, Tobias,Paulus, Beate,Schalley, Christoph A.
supporting information, p. 2877 - 2883 (2017/03/08)
Rigidity and preorganisation are believed to be required for high affinity in multiply bonded supramolecular complexes as they help reduce the entropic penalty of the binding event. This comes at the price that such rigid complexes are sensitive to small geometric mismatches. In marked contrast, nature uses more flexible building blocks. Thus, one might consider putting the rigidity/high-affinity notion to the test. Multivalent crown/ammonium complexes are ideal for this purpose as the monovalent interaction is well understood. A series of divalent complexes with different spacer lengths and rigidities has thus been analysed to correlate chelate cooperativities and spacer properties. Too long spacers reduce chelate cooperativity compared to exactly matching ones. However, in contrast to expectation, flexible guests bind with chelate cooperativities clearly exceeding those of rigid structures. Flexible spacers adapt to small geometric host–guest mismatches. Spacer–spacer interactions help overcome the entropic penalty of conformational fixation during binding and a delicate balance of preorganisation and adaptability is at play in multivalent complexes.
Palladium-catalysed and phosphine-promoted synthesis of diaryl ethers through self-coupling
Wang, Dawei,Xu, Zhaojun,Yu, Xiaoli,Li, Yongliang,Wan, Huida
, p. 691 - 693 (2016/11/18)
An efficient, palladium acetate-catalysed, tributylphosphine-promoted direct synthesis of symmetrical diaryl ethers through the self-coupling of aryl fluorides has been developed with K2CO3/ZrO2 as a base. This provides an alternative method to prepare aromatic polymers, important synthetic intermediates and natural products for use in the field of pharmaceuticals and industrial materials.
