87586-49-0Relevant academic research and scientific papers
Oxidative coupling of dichloroaluminium phenolates: Highly selective synthesis of hydroxylated Bi- and tetraaryls
Sartori, Giovanni,Maggi, Raimondo,Bigi, Franca,Arienti, Attilio,Casnati, Giuseppe,Bocelli, Gabriele,Mori, Giovanni
, p. 9483 - 9494 (2007/10/02)
Dichloroaluminium phenolates 4 undergo highly selective FeCl3-promoted oxidative coupling. Variously substituted symmetric 2,2′-dihydroxy biaryls 2 are obtained in good yields and excellent selectivities. The chelation control in the final reaction products 7 promotes the chemoselectivity of the process.
Autoxidation of Phenols Catalyzed by Copper(II)-Ethylenediamine Complexes: The Reaction Mechanism
Kushioka, Keiko
, p. 4456 - 4459 (2007/10/02)
The mechanism of the autoxidation of phenols with molecular oxygen catalyzed by Cu(II)-ethylenediamine complexes is elucidated.The kinetics are of first order in both and and of one-half order in .Those results imply the formation of a oxygen-bridged complex in the course of the reaction.The C-C coupling of two phenoxy radicals is facilitated within the coordination sphere of Cu(II) and affords the primary oxidation products, i. e. 2,2'-biphenyldiols.The bulkiness of substituents determines the type of the secondary products and either benzofuran or dioxepin is produced.Taking into account the results of oxidation of 2,2'-biphenyldiols, the mechanism of the production of benzofuran and dioxepin is also clarified.In the Cu(II) complex with sterically crowded biphenyldiolate, the oxidation activity of Cu(II) has been enhanced and the coordinating biphenyldiolate is immediately oxidized to benzofuran.On the contrary, the biphenyldiolate-Cu(II) complex with square-planar geometry could not produce benzofuran.After the complex is forced into the active tetrahedral configuration by the access of phenoxy radical-Cu(II) complex, the biphenyldiolate is oxidized to biphenyloxy radical and suffers C-O coupling with the phenoxy radical to afford dioxepin.
Catalytic Activity of Copper(II)-Ethylenediamine Complexes in Autoxidation of Phenols
Kushioka, Keiko
, p. 4948 - 4950 (2007/10/02)
Studies of the autoxidation of tert-butylphenols 1-4 with molecular oxygen in the presence of Cu(II) complexes of N-substituted ethylenediamines indicate that the most catalytically active complexes are sterically crowded around the nitrogen atoms.The principal primary oxidation products formed in the presence of these complexes are substituted biphenyls 5, 7, 10, and 14, the first three of which are converted into secondary products on prolonged oxidation.Only in the oxidation of 2 is a diphenyl ether (9) formed, in quantities that increase little after the first 5 min of oxidation.
