18052-80-7Relevant academic research and scientific papers
Addition and cyclization reactions in the thermal conversion of hydrocarbons with an enyne structure, 5: High-temperature ring closures of 1,3-hexadien-5-ynes to naphthalenes - Competing reactions via isoaromatics, alkenylidene carbenes, and vinyl-type radicals
Hofmann, Joerg,Schulz, Kathrin,Altmann, Annett,Findeisen, Matthias,Zimmermann, Gerhard
, p. 2541 - 2548 (1997)
The 4-substituted 1-phenyl-1-butene-3-ynes 1a-c and the 2-ethynylstyrenes 7a-c were subjected to high-temperature pyrolysis. The cycloisomerization products isolated suggest that these are formed by three competing processes: by (i) an electrocyclic or a molecule-induced, (ii) an alkenylidene carbene controlled, and (iii) a radical-controlled ring-closure . To estimate the relative importance of these three reactions here mentioned, the substrates have been isomerized in oxygen-free nitrogen and in nitrogen proportionally substituted by toluene at 700 and 650°C, respectively. The relative contributions of these isomerizations depend not only on the conversion temperature but also on the substituent R in 1 or 7. Wiley-VCH Verlag GmbH, 1997.
Time-resolved fluorescence of α,ω-di(1-naphthyl)oligosilanes and 1-naphthyloligosilanes: Intramolecular excimer formation and charge-transfer interactions
Karatsu, Takashi,Nakamura, Takashi,Terasawa, Masato,Yagai, Shiki,Kitamura, Akihide,Nishimura, Yoshinobu,Yamazaki, Iwao
, p. 347 - 357 (2013)
The intramolecular photochemical processes excimer formation and charge-transfer (CT) complex formation were investigated by comparing the behavior of α,ω-di(1-naphthyl)permethyloligosilanes ((1-naphthyl)-(SiMe2) n -(1-naphthyl); NS n N, n = 1, 3, and 6) and 1-(1-naphthyl)permethyloligosilanes ((1-naphthyl)-(SiMe2) n -Me; NS n, n = 1, 3, and 6) by use of stationary and time-resolved fluorescence (TR-FL) measurements. Formation of excimer and CT complexes is highly dependent on the silicon chain length and polarity of the medium. Graphical Abstract: Intramolecular excimer formation between the two naphthyl groups and charge transfer interactions between the naphthyl and silane moieties were investigated by use of a time-correlated single-photon counting method.[Figure not available: see fulltext.]
Protodesilylation of Arylsilanes by Visible-Light Photocatalysis
García Manche?o, Olga,Kuhlmann, Jan H.,Uygur, Mustafa
supporting information, p. 1689 - 1694 (2022/03/14)
The first visible-light-mediated photocatalytic, metal- and base-free protodesilylation of arylsilanes is presented. The C(sp2)-Si bond cleavage process is catalyzed by a 5 mol % loading of a commercially available acridinium salt upon blue-light irradiation. Two simple approaches have been identified employing either aerobic or hydrogen atom transfer cocatalytic conditions, which enable the efficient and selective desilylation of a broad variety of simple and complex arylsilanes under mild conditions.
Generation of Aryllithium Reagents from N -Arylpyrroles Using Lithium
Ozaki, Tomoya,Kaga, Atsushi,Saito, Hayate,Yorimitsu, Hideki
, p. 3019 - 3028 (2021/06/02)
Treatment of 1-aryl-2,5-diphenylpyrroles with lithium powder in tetrahydrofuran at 0 °C results in the generation of the corresponding aryllithium reagents through reductive C-N bond cleavage.
Cobalt-Catalyzed Defluorosilylation of Aryl Fluorides via Grignard Reagent Formation
Cho, Hyungdo,Cho, Seung Hwan,Jang, Minjae,Jeong, Jongheon,Kim, Hyunseok,Lee, Eunsung,Lim, Soobin
supporting information, p. 7387 - 7392 (2020/10/12)
Transition-metal-catalyzed transformations of the carbon-fluorine bond not only tackle an interesting problem of challenging bond activation but also offer new synthetic strategies where the relatively inert C-F bond is converted to versatile functional groups. Herein we report a practical cobalt-catalyzed silylation of aryl fluorides that uses a cheap electrophilic silicon source with magnesium. This method is compatible with various silicon sources and can be operated under aerobic conditions. Mechanistic studies support the in situ formation of a Grignard reagent, which is captured by the electrophilic silicon source.
Nickel-Catalyzed Decarbonylation of Acylsilanes
Ito, Yuri,Kodama, Takuya,Nakatani, Syun,Sakurai, Shun,Tobisu, Mamoru
, p. 7588 - 7594 (2020/06/27)
Nickel-catalyzed decarbonylation of acylsilanes is developed. In sharp contrast to cross-coupling reactions of acylsilanes, in which the silyl group serves as a leaving group, the silyl group is retained in the product in this decarbonylation reaction. Although the strong binding of the dissociated CO to the nickel center frequently hinders catalyst turnover in nickel-mediated decarbonylative reactions, this reaction can be catalyzed by nickel complexes bearing a CO ligand.
Nickel-catalyzed cross-coupling reaction of carbamates with silylmagnesium reagents
Murugesan, Vetrivelan,Balakrishnan, Venkadesh,Rasappan, Ramesh
, p. 293 - 298 (2019/08/12)
The C–O bonds are kinetically inert in cross-coupling reactions compared to those of carbon–halogen bonds. Thus, developing methodologies for the activation of C–O bonds in cross-coupling reactions remains a major challenge. We disclose an unprecedented nickel mediated cross-coupling of carbamates with silylmagnesium reagents that does not require the expensive silylboranes. Silylmagnesium reagents were prepared from either silyllithium or silyl iodides. This methodology is distinguished by the synthesis of trimethylsilyl coupled product and its synthetic applications. Kinetic studies and radical clock experiments revealed the rate-limiting C–O bond cleavage, half order with respect to the catalyst and a non-radical transition state.
Absorption and fluorescence spectroscopic properties of 1- and 1,4-silyl-substituted naphthalene derivatives
Maeda, Hajime,Maeda, Tomohiro,Mizuno, Kazuhiko
, p. 5108 - 5125 (2012/08/28)
Silyl-substituted naphthalene derivatives at the 1- and 1,4-positions were synthesized and their UV absorption, fluorescence spectroscopic properties, and fluorescence lifetimes were determined. Analysis of the results shows that the introduction of silyl groups at these positions of the naphthalene chromophore/fluorophore causes shifts of the absorption maxima to longer wavelengths and increases in fluorescence intensities. Bathochromic shifts of the absorption maxima and increases in fluorescence intensities are also promoted by the introduction of methoxy and cyano groups at the naphthalene 4- and 5-positions. In addition, the fluorescence of 9,10-dicyanoanthracene is efficiently quenched by these naphthalene derivatives with Stern-Volmer plot calculated rate constants that depend on the steric bulk of the silyl groups.
Gold-catalysed oxyarylation of styrenes and mono- and gem-disubstituted olefins facilitated by an iodine(III) oxidant
Ball, Liam T.,Lloyd-Jones, Guy C.,Russell, Christopher A.
supporting information; experimental part, p. 2931 - 2937 (2012/04/23)
1-Hydroxy-1,2-benziodoxol-3(1H)-one (IBA) is an efficient terminal oxidant for gold-catalysed, three-component oxyarylation reactions. The use of this iodine(III) reagent expands the scope of oxyarylation to include styrenes and gem-disubstituted olefins, substrates that are incompatible with the previously reported Selectfluor-based methodology. Diverse arylsilane coupling partners can be employed, and in benzotrifluoride, homocoupling is substantially reduced. In addition, the IBA-derived co-products can be recovered and recycled. The I's have it: The unprecedented use of an iodine(III) reagent as the terminal oxidant for gold-catalysed oxyarylation allows the substrate scope to be significantly expanded; in addition to monosubstituted olefins, styrenes and gem-disubstituted olefins are well tolerated (see scheme). With benzotrifluoride as solvent, unproductive homodimerisation of the arylsilane coupling partner is effectively suppressed. Copyright
Rhodium-catalyzed silylation and intramolecular arylation of nitriles via the silicon-assisted cleavage of carbon-cyano bonds
Tobisu, Mamoru,Kita, Yusuke,Ano, Yusuke,Chatani, Naoto
supporting information; experimental part, p. 15982 - 15989 (2009/05/16)
A rhodium-catalyzed silylation reaction of carbon - cyano bonds using disilane has been developed. Under these catalytic conditions, carbon-cyano bonds in aryl, alkenyl, allyl, and benzyl cyanides bearing a variety of functional groups can be silylated. The observation of an enamine side product in the silylation of benzyl cyanides and related stoichiometric studies indicate that the carbon-cyano bond cleavage proceeds through the deinsertion of silyl isocyanide from η2-iminoacyl complex B. Knowledge gained from these studies has led to the development of a new intramolecular biaryl coupling reaction in which aryl cyanides and aryl chlorides are cross-coupled.
