2417-04-1Relevant articles and documents
Selective oxidative para C-C dimerization of 2,6-dimethylphenol
Boldron, Christophe,Aromi, Guillem,Challa, Ger,Gamez, Patrick,Reedijk, Jan
, p. 5808 - 5810 (2005)
Mechanistic investigations on the oxidative coupling of 2,6-dimethylphenol have led to the development of a selective and efficient procedure to prepare 3,5,3′,5′-tetramethyl-biphenyl-4,4′-diol, via a C-C coupling, mediated by a hypervalent form of iodine, i.e. (diacetoxyiodo)benzene and for which a mechanism is proposed. The Royal Society of Chemistry 2005.
Regioselective oxidative coupling of 2,6-dimethylphenol to tetramethyldiphenoquinone using polyamine dendrimer-encapsulated Cu catalysts
Maeno, Zen,Okao, Motohiro,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
, p. 9662 - 9665 (2013)
The polyamine dendrimer-encapsulated Cu complexes are capable of regioselectively catalyzing the oxidative coupling reaction of 2,6-dimethylphenol to tetramethyldiphenoquinone in high yield. The polyamine dendrimer nanovoids encapsulate Cu ions in such a manner that adjacent Cu centers are able to serve as active species for the reaction.
A dual-functional heterogeneous ruthenium catalyst for the green one-pot synthesis of biphenols
Maeno, Zen,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro
, p. 3205 - 3209 (2017/08/16)
A green one-pot synthesis of biphenols using O2 and H2 was achieved using a magadiite-supported Ru nanoparticle catalyst. This catalyst selectively promoted the oxidative coupling of phenols to diphenoquinones with O2, followed by the successive reduction of these diphenoquinones to biphenols using H2 in a single reactor.
Solvent-Dependent Facile Synthesis of Diaryl Selenides and Biphenols Employing Selenium Dioxide
Quell, Thomas,Mirion, Michael,Schollmeyer, Dieter,Dyballa, Katrin M.,Franke, Robert,Waldvogel, Siegfried R.
, p. 115 - 119 (2016/05/02)
Biphenols are important structure motifs for ligand systems in organic catalysis and are therefore included in the category of so-called "privileged ligands". We have developed a new synthetic pathway to construct these structures by the use of selenium dioxide, a stable, powerful, and commercially available oxidizer. Our new, and easy to perform protocol gives rise to biphenols and diaryl selenides depending on the solvent employed. Oxidative treatment of phenols in acetic acid yields the corresponding biphenols, whereas conversion in pyridine results in the preferred formation of diaryl selenides. As a consequence, we were able to isolate a broad scope of novel diaryl selenides, which could act as pincer-like ligands with further applications in organic synthesis or as ligands in transition metal catalysis.
Industrialized synthesis method of high-purity biphenyl diphenol compound
-
Paragraph 0023; 0024, (2016/11/14)
The invention discloses an industrialized synthesis method of a high-purity biphenyl diphenol compound. The synthesis method comprises the steps that a phenolic compound A of which the ortho-position or para-position is a hydrogen atom serves as the raw material, alkali metal hydroxide or alkaline earth metal hydroxide or weak-acid alkali metal salt serves as a catalyst, different phenolic compounds are added to serve as oxidation regulators, all the substances are mixed and heated to 65 DEG C-185 DEG C, and meanwhile oxygen or air is blown into the mixture for an oxidation coupling reaction; after the PH value of the reaction system is adjusted through an acidic substance, a disproportionated reaction is conducted in an inert gas environment at the temperature ranging from 65 DEG C to 245 DEG C, and the high-purity biphenyl diphenol compound B or C is obtained. According to the preparation method of the high-purity biphenyl diphenol compound, the steps are simple, the reaction conditions are mild, the cost is low, the reaction materials can be recycled, the product is good in color, the product purity reaches up to 99.9 percent, and the preparation method is very suitable for industrialized production.
Selective c-c coupling reaction of dimethylphenol to tetramethyldiphenoquinone using molecular oxygen catalyzed by cu complexes immobilized in nanospaces of structurally-ordered materials
Maeno, Zen,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
, p. 3089 - 3106 (2015/09/02)
Two high-performance Cu catalysts were successfully developed by immobilization of Cu ions in the nanospaces of poly(propylene imine) (PPI) dendrimer and magadiite for the selective C-C coupling of 2,6-dimethylphenol (DMP) to 3,3′,5,5′-tetramethyldiphenoquinone (DPQ) with O2 as a green oxidant. The PPI dendrimer encapsulated Cu ions in the internal nanovoids to form adjacent Cu species, which exhibited significantly high catalytic activity for the regioselective coupling reaction of DMP compared to previously reported enzyme and metal complex catalysts. The magadiite-immobilized Cu complex acted as a selective heterogeneous catalyst for the oxidative C-C coupling of DMP to DPQ. This heterogeneous catalyst was recoverable from the reaction mixture by simple filtration, reusable without loss of efficiency, and applicable to a continuous flow reactor system. Detailed characterization using ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR), electronic spin resonance (ESR), and X-ray absorption fine structure (XAFS) spectroscopies and the reaction mechanism investigation revealed that the high catalytic performances of these Cu catalysts were ascribed to the adjacent Cu species generated within the nanospaces of the PPI dendrimer and magadiite.
Selective oxidative homo-and cross-coupling of phenols with aerobic catalysts
Lee, Young Eun,Cao, Trung,Torruellas, Carilyn,Kozlowski, Marisa C.
supporting information, p. 6782 - 6785 (2014/06/09)
Simple catalysts that use atom-economical oxygen as the terminal oxidant to accomplish selective ortho-ortho, ortho-para, or para-para homo-couplings of phenols are described. In addition, chromium salen catalysts have been discovered as uniquely effective in the cross-coupling of different phenols with high chemo-and regioselectivity.
{Cu2+-Co3+-Cu2+} and {Cu 2+-Fe3+-Cu2+} heterobimetallic complexes and their catalytic properties
Srivastava, Sumit,Ali, Afsar,Tyagi, Adish,Gupta, Rajeev
, p. 2113 - 2123 (2014/05/06)
We report on the heterobimetallic complexes {Cu+-Co 3+-Cu+} (3), {Cu+-Fe3+-Cu +} (4), {Cu2+-Co3+-Cu2+} (5), and {Cu2+-Fe3+-Cu2+} (6) and show their catalytic applications in the oxidation of hindered phenols and the oxidative coupling of terminal alkynes. The former reaction produces C-C-coupled and dealkylated products, whereas the latter leads to the homo- and heterocoupling of terminal alkynes. The facile redox interconversion between Cu+ and Cu 2+ for the secondary metal ions in these heterobimetallic complexes appears to be essential for the observed catalysis, and an important design aspect is better substrate accessibility and the use of molecular oxygen as the sole oxidant. Heterobimetallic complexes {Cu+-Co3+-Cu +} (3), {Cu+-Fe3+-Cu+} (4), {Cu 2+-Co3+-Cu2+} (5), and {Cu2+-Fe 3+-Cu2+} (6) have been used as catalysts for the oxidation of substituted phenols and the oxidative homo- and heterocoupling of terminal alkynes. Copyright
{Cu2+-Co3+-Cu2+} and {Cu2+-Fe3+-Cu2+} heterobimetallic complexes and their catalytic properties
Srivastava, Sumit,Ali, Afsar,Tyagi, Adish,Gupta, Rajeev
, p. 2113 - 2123 (2015/04/27)
We report on the heterobimetallic complexes {Cu+-Co3+-Cu+} (3), {Cu+-Fe3+-Cu+} (4), {Cu2+-Co3+-Cu2+} (5), and {Cu2+-Fe3+-Cu2+} (6) and show their catalytic applications in the oxidation of hindered phenols and the oxidative coupling of terminal alkynes. The former reaction produces C-C-coupled and dealkylated products, whereas the latter leads to the homo- and heterocoupling of terminal alkynes. The facile redox interconversion between Cu+ and Cu2+ for the secondary metal ions in these heterobimetallic complexes appears to be essential for the observed catalysis, and an important design aspect is better substrate accessibility and the use of molecular oxygen as the sole oxidant. Heterobimetallic complexes {Cu+-Co3+-Cu+} (3), {Cu+-Fe3+-Cu+} (4), {Cu2+-Co3+-Cu2+} (5), and {Cu2+-Fe3+-Cu2+} (6) have been used as catalysts for the oxidation of substituted phenols and the oxidative homo- and heterocoupling of terminal alkynes.
Efficient oxidative coupling of 2,6-disubstituted phenol catalyzed by a dicopper(II) complex
Liao, Bei-Sih,Liu, Yi-Hung,Peng, Shei-Ming,Liu, Shiuh-Tzung
scheme or table, p. 1158 - 1164 (2012/03/07)
Complexation of a rigid multi-pyridine ligand bis(2-pyridyl)-1,8- naphthyridine (bpnp) with [Cu2(TFA)4] (TFA = trifluoroacetate) resulted in the formation of a dinuclear copper(ii) complex, namely [Cu2(bpnp)(μ-OH)(TFA)3] (1). This complex has been characterized by X-ray crystallographic, spectroscopic and elemental analyses. Complex 1 is an efficient catalyst for the oxidative coupling of various 2,6-disubstituted phenols with molecular oxygen. Yields and selectivity depend on the reaction conditions employed, the best results being obtained in isopropanol or dioxane at 90 °C with yields of >99%. Mechanistic pathway of the catalysis is discussed.
