7575-08-8Relevant academic research and scientific papers
Aerobic Oxidative Intramolecular Aromatic Coupling via Heterogeneous Metal Catalysts
Fujimoto, Shigenobu,Matsumoto, Kenji,Shindo, Mitsuru
supporting information, p. 3057 - 3061 (2016/10/09)
An aerobic, heterogeneously catalyzed oxidative intramolecular coupling reaction of aromatic compounds is reported here. Using commercially available, recyclable heterogeneous metal catalysts, the coupling reactions of o-terphenyls and 1,ω-biarylalkanes proceeded quickly under mild conditions, i.e., at room temperature under oxygen as a co-oxidant almost all within 1 h, to provide the corresponding coupled products like triphenylenes and phenanthrenes in good to excellent yields. This reaction is an easily handled, practical, and atom-economical coupling method, which is of great importance in modern organic syntheses. (Figure presented.).
Palladium-Catalyzed Domino Process: Synthesis of Symmetrical Diarylalkynes, cis- and trans-Alkenes using Lithium Acetylide as a Synthon
Krishna, Jonnada,Krishna Reddy, Alavala Gopi,Satyanarayana, Gedu
, p. 3597 - 3610 (2016/01/25)
An efficient domino protocol has been developed for the synthesis of symmetrical diarylalkynes. Notably, the method was successful in the presence of a palladium catalyst without the support of a copper co-catalyst. Significantly, the method enabled the use of the commercially available and cheap lithium acetylide ethylenediamine complex as a source of acetylene for the construction of dual C-C bonds, with a wide range of compatibility towards various substituents of the aryl bromides/iodides. Significantly, this protocol was successfully applied to the synthesis of cis- and trans-alkenes in a highly stereoselective manner in a sequential one-pot process.
Total synthesis of the marine metabolite (±)-Polysiphenol via highly regioselective intramolecular oxidative coupling
Barrett, Tim N.,Braddock, D. Christopher,Monta, Anna,Webb, Michael R.,White, Andrew J.P.
supporting information; experimental part, p. 1980 - 1984 (2011/11/11)
(±)-Polysiphenol (1), an atropisomerically stable 4,5-dibrominated 9,10-dihydrophenanthrene from Polysiphonia ferulacea, was prepared by a biomimetically inspired highly regioselective intramolecular oxidative coupling of a dibrominated dihydrostilbene. T
McMurry coupling of aryl aldehydes and imino pinacol coupling mediated by Ti(O-i-Pr)4/Me3SiCl/Mg reagent
Okamoto, Sentaro,He, Jing-Qian,Ohno, Chihaya,Oh-iwa, Yuhji,Kawaguchi, Yuhki
experimental part, p. 387 - 390 (2010/03/03)
Ti(O-i-Pr)4/Me3SiCl/Mg reagent mediated McMurry coupling of aryl aldehydes to biaryl olefins at near room temperature. This low valent titanium (LVT) reagent also mediated the coupling of aldimines to 1,2-diamines (imino pinacol coupling).
A simple route to new phenanthro- and phenanthroid-fused thiazoles by a PIFA-mediated (hetero)biaryl coupling reaction
Moreno, Isabel,Tellitu, Imanol,Dominguez, Esther,SanMartin, Raul
, p. 2126 - 2135 (2007/10/03)
An application of the PIFA-mediated [PIFA: phenyliodine(III) bis(trifluoroacetate) biaryl coupling reaction is presented and extended to the formation of heterobiaryl connections. A preliminary study of the scope and limitations of this procedure was carried out in the synthesis of phenanthroids 11 from a series of phenethyl-substituted heterocycles 10, It was observed that in some cases a competitive dimerization process took place. It was also found that the coupling step could be efficiently extended to a larger number of examples if an aromatic ring were situated fused to the 1,2-diarylethane skeleton, as in 23 and 30. The synthesis of a series of 4,5-diarylthiazoles 23a-g was therefore carried out to explore the electronic requirements and the regioselectivity of the PIFA-mediated non-phenolic coupling reaction. When the same procedure was applied to aryl-heteroarylthiazoles 30, a series of phenanthroid-fused thiazoles 31 was obtained in good overall yields. To the best of our knowledge, no oxidative aryl-heteroaryl coupling reaction of this type had previously been reported. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
The photochemistry of 3,3′,4,4′-tetramethoxyand 4-hydroxy-3,3′,4 -trimethoxystilbene -models for stilbene chromophores in peroxide-bleached, high-yield wood pulps
Leigh, William J.,Johnathan Lewis,Lin, Vincent,Alberto Postigo
, p. 263 - 275 (2007/10/03)
The photochemistry of the title compounds has been investigated in ethanol and tetrahydrofuran solution under aerobic and anaerobic conditions. Direct irradiation of trans-3,3′,4,4′-tetramethoxystilbene (trans-1) in deoxygenated ethanol leads to the rapid establishment of a photostationary state with the cis isomer, and the slower formation of the ethyl ether corresponding to addition of ethanol across the olefinic C=C bond and cyclobutane dimers. The same products are formed upon photolysis in the presence of oxygen under the same conditions but, in addition, two isomeric tetramethoxyphenanthrenes and 3,4-dimethoxybenzaldehyde are formed. Photolysis of trans-1 in oxygenated tetrahydrofuran leads to the same products in different relative yields. Quantum yields for cis,trans photoisomerization, phenanthrene formation, and addition of ethanol have been determined by ferrioxalate actinometry. Direct irradiation of trams-4-hydroxy-3,3′,4′-trimethoxystilbene (trans-2) in ethanol solution also results in rapid cis-trans isomerization and the formation of (three) isomeric phenanthrene derivatives in photolyses carried out in the presence of oxygen, although the material balance is low. The various products of photolysis of trans-2 have been independently synthesized by desilylation of the products isolated from photolysis of trans-4-tertbutyldimethylsiloxy-3,3′,4′-trimethoxystilbene (trans-3) under similar conditions. Fluorescence-quenching experiments have been carried out to determine the relative rates of quenching of the excited singlet states of trans-1 and trans-2 by alcohols and oxygen. The formation of aldehydes is proposed to arise via reaction of Superoxide ion with stilbene radical cations, which are formed by electron-transfer quenching of the stilbene excited singlet state by oxygen.
REDUCTIVE COUPLING OF BENZOIC ACID HALIDES AND ESTERS USING LOW-VALENT TITANIUM
Dang, Y.,Geise, H. J.
, p. 375 - 380 (2007/10/02)
The reductive coupling of (substituted) benzoic acid chlorides and esters is achieved using low-valent titanium, generated from TiCl3 and LiAlH4.Both acid chlorides and esters seem to follow the same two reaction pathways: one path via tolanes to stilbenes, the other via benzils to complex mixtures of products arising from reduction and further coupling reactions.Although the exact product balance depends upon the reaction conditions the major product is (substituted) cis-stilbene.
