1083-56-3Relevant articles and documents
Catalytic activity of the titanocene complex with tolane in homogeneous hydrogenation of unsaturated hydrocarbons
Shur, V.B.,Burlakow, V.V.,Vol'pin, M.E.
, p. 303 - 308 (1992)
The titanocene complex with tolane, Cp2Ti(C2Ph2), is an effective catalyst for homogeneous hydrogenation of olefins and acetylenes at room temperature and atmospheric pressure.In the absence of unsaturated substrate, the complex readily reacts with molecu
THE CHEMISTRY OF ORGANOBISMUTH REAGENTS PART XIII LIGAND COUPLING INDUCED BY Pd(0)
Barton, Derek H. R.,Ozbalik, Nubar,Ramesh, Manian
, p. 5661 - 5668 (1988)
Palladium zero converts triphenylbismuth quantitatively to diphenyl and metallic bismuth.many other derivatives of Bi(III) and Bi(V) are similarly transformed to diaryls in excellent yield.Similar reactions with triphenylantimony and with perphenyl lead derivatives suggest that number of non-transition metal elements should show similar behaviour.Acid chlorides also react under mild conditions with triphenylbismuth under catalysis by palladium(0) to furnish phenylketones in excellent yield (with respect to the triphenylbismuth).All three phenyls are transferred when a suitable excess of the acid chloride is used.Diaryl formation is a minor side reaction.
Regiochemistry of the styrene insertion with CH2-bridged ansa-zirconocene-based catalysts
Izzo, Lorella,Napoli, Mariagrazia,Oliva, Leone
, p. 9340 - 9345 (2003)
Methylenebis(indenyl)zirconium dichloride substituted in C(3), activated by methylalumoxane, is able to give polystyrene and ethylene-styrene copolymers. In this study hydrooligomers, whose structure, determined by 13C NMR and GC-MS techniques, gives information about the regiochemistry and the stereochemistry of styrene insertion, have been purposefully prepared. The regiochemistry of the styrene insertion is related to the encumbrance of substituents in C(3). rac-[Methylene-(3-R-1-indenyl)2]ZrCl2 with R = H, CH3, or CH2CH3 induces a prevailingly secondary styrene insertion into the zirconium-carbon bond. With increasing the substituent's steric hindrance (R = CH(CH3)2), regiochemistry inversion occurs and the primary insertion becomes prevailing. The analysis of ethylene-styrene copolymers obtained in the presence of the different catalysts allows confirming the correlation between regiochemistry and comonomers' reactivity. Besides, also the stereospecificity can be evaluated from the structure of the hydrotrimers, when the insertion is primary. Whereas the isospecificity in the absence of substituents (secondary insertion) and in the presence of the tert-butyl substituent (primary insertion) is well-known, a surprising syndiospecificity is observed when the indenyl ligand bears the isopropyl substituent in C(3).
Ligand-accelerated ortho -C-H alkylation of arylcarboxylic acids using alkyl boron reagents
Thuy-Boun, Peter S.,Villa, Giorgio,Dang, Devin,Richardson, Paul,Su, Shun,Yu, Jin-Quan
, p. 17508 - 17513 (2013)
A protocol for the Pd(II)-catalyzed ortho-C-H alkylation of phenylacetic and benzoic acids using alkylboron reagents is disclosed. Monoprotected amino acid ligands (MPAA) were found to significantly promote reactivity. Both potassium alkyltrifluoroborates and alkylboronic acids were compatible coupling partners. The possibility of a radical alkyl transfer to Pd(II) was also investigated.
Unexpected formation of 1,4-diphenylbutylphosphinic acid from 1,4-diphenylbuta-1,3-diene and elemental phosphorus via the Trofimov–Gusarova reaction
Artem'ev, Alexander V.,Sutyrina, Anastasiya O.,Matveeva, Elena A.,Albanov, Alexander I.,Klyba, Lyudmila V.
, p. 137 - 138 (2017)
trans,trans-1,4-Diphenylbuta-1,3-diene reacts with elemental (red) phosphorus in the superbasic KOH / DMSO (H2O) system (120?°C, 3 h) to give, after acidic work-up, 1,4-diphenylbutylphosphinic acid in 48% yield.
Synthesis and transformations of 4-phenylethynyl- and 4-styrylpyrazolo[5,1-c][1,2,4]triazines
Ivanov, Sergey M.,Koltun, Denis S.
, p. 656 - 665 (2021)
[Figure not available: see fulltext.] Rearrangements of 3-tert-butyl-8-methyl-4-phenylethynyl-1,4-dihydropyrazolo[5,1-c][1,2,4]triazine derivatives by the action of bases led to the formation of aromatic (E)- or (Z)-4-styryl-functionalized compounds. At t
Microwave-assisted cross-coupling and hydrogenation chemistry by using heterogeneous transition-metal catalysts: An evaluation of the role of selective catalyst heating
Irfan, Muhammed,Fuchs, Michael,Glasnov, Toma N.,Kappe, C. Oliver
, p. 11608 - 11618 (2009)
The concept of specific microwave effects in solid/liquid catalytic processes resulting from the selective heating of a microwave-absorbing heterogeneous transition-metal catalyst by using 2.45 GHz microwave irradiation was evaluated. As model transformations Ni/C-, Cu/C-, Pd/C-, and Pd/ Al 2O3-catalyzed carbon-carbon/ carbon-heteroatom cross-couplings and hydrogenation reactions were investigated. To probe the existence of specific microwave effects by means of selective catalyst heating in these transformations, control experiments comparing microwave dielectric heating and conventional thermal heating at the same reaction temperature were performed. Although the supported metal catalysts were experimentally found to be strongly microwave absorbing, for all chemistry examples investigated herein no differences in reaction rate or selectivity between microwave and conventional heating experiments under carefully controlled conditions were observed. This was true also for reactions that use low-absorbing or microwave transparent solvents, and was independent of the microwave absorbtivity of the catalyst support material. In the case of hydrogenation reactions, the stirring speed was found to be a critical factor on the mass transfer between gas and liquid phase, influencing the rate of the hydrogenation in both microwave and conventionally heated experiments.
Cycloalkane-based thermomorphic systems for organic electrochemistry: An application to Kolbe-coupling
Okada, Yohei,Kamimura, Kazuya,Chiba, Kazuhiro
, p. 5857 - 5862 (2012)
The discovery that cycloalkanes can form thermomorphic systems with typical polar organic solvents has led to the development of less-polar electrolyte solutions. Their mixing and separation can be regulated reversibly at a moderate temperature range. The phase switching temperature can be controlled by changing the solvent compositions. While biphasic conditions are maintained below the phase switching temperature, conductive monophasic conditions as less-polar electrolyte solutions are obtained above the phase switching temperature. After the electrochemical transformations, biphasic conditions are reconstructed below the phase switching temperature, facilitating the separation of cycloalkane where hydrophobic products or designed hydrophobic platforms are selectively partitioned. Several polar organic solvents, including acetonitrile, methanol, and pyridine, can be used in this system according to the requirement of the reactions.
Detection of living anionic species in polymerization reactions using hyperpolarized NMR
Lee, Youngbok,Heo, Gyu Seong,Zeng, Haifeng,Wooley, Karen L.,Hilty, Christian
, p. 4636 - 4639 (2013)
Intermediates during the anionic polymerization of styrene were observed using hyperpolarized NMR. Dissolution dynamic nuclear polarization (DNP) of monomers provides a sufficient signal-to-noise ratio for detection of 13C NMR signals in real t
Ni-catalyzed reductive homocoupling of unactivated alkyl bromides at room temperature and its synthetic application
Peng, Yu,Luo, Long,Yan, Chang-Song,Zhang, Jian-Jian,Wang, Ya-Wen
, p. 10960 - 10967 (2013)
A room-temperature Ni-catalyzed reductive approach to homocoupling of unactivated primary, secondary, and tertiary alkyl bromides is described. The catalytic system can be easily generated from air-stable and cheap materials and demonstrates broad functional group tolerance, thus allowing facile access to useful dimeric triterpene and lignan-like molecules. Moreover, the dimerization of tertiary bromide 6 efficiently establishes sterically hindered vicinal quaternary carbons (C3a and C3a′), which is a key linkage of intriguing bispyrrolo[2,3-b]indoline alkaloids, thereby enabling us to complete the total syntheses of racemic chimonanthine (9) and folicanthine (10). In addition, this dimerization method can be expanded to the highly stereoselective synthesis of bisperhydrofuro[2,3-b]furan (5a) and the dimeric spiroketal 5b, signifying the involvement of possible radical species.
