25570-02-9Relevant academic research and scientific papers
Discovery and mechanistic investigation of Pt-catalyzed oxidative homocoupling of benzene with PhI(OAc)2
Abu-Omar, Mahdi M.,Nabavizadeh, S. Masoud,Niroomand Hosseini, Fatemeh,Park, Chan,Wu, Guang
supporting information, p. 2477 - 2486 (2020/03/05)
We present a Pt-catalyzed direct coupling of benzene to biphenyl. This catalytic reaction employs a cyclometalated platinum(ii) complex [PtMe(bhq)(SMe2)] (bhq = benzo[h]quinolate) with PhI(OAc)2 as an oxidant and does not require an acid, a co-catalyst or a solvent. The reaction kinetics and characterization of potential catalytic species are reported. The reaction is first-order in Pt and second-order in benzene, which implicates the second C-H activation step as rate-determining. A Pt(ii)/Pt(iv) catalytic cycle is suggested. The reaction commences by oxidation of the Pt(ii) complex to give the platinum(iv) species [Pt(bhq)(SMe2)(OAc)2](OAc) followed by C-H activation of benzene to afford the intermediate [PtPh(bhq)(SMe2)(OAc)](OAc) concurrently with the release of HOAc. A second benzene molecule reacts similarly to give the diphenyl intermediate [PtPh2(bhq)(SMe2)](OAc). C-C bond forming reductive elimination ensues to regenerate Pt(ii) and complete the catalytic cycle. The proposed mechanism has been examined by DFT computations, which provide support to experimental findings.
Improved procedure for single-electron-transfer-induced grignard cross-coupling reaction
Shirakawa, Eiji,Okura, Keisho,Uchiyama, Nanase,Murakami, Takuya,Hayashi, Tamio
, p. 922 - 924 (2014/06/23)
Aryl Grignard reagents were found to undergo coupling with aryl or alkenyl bromides in the presence of LiCl in a mixed solvent consisting of toluene and THF (2/1). Previously employed removal of THF with evacuation from Grignard solutions is no longer needed to obtain biaryls and styrene derivatives.
Cobalt-catalyzed electrophilic amination of arylzincs with N-chloroamines
Qian, Xin,Yu, Zailu,Auffrant, Audrey,Gosmini, Corinne
supporting information, p. 6225 - 6229 (2013/07/05)
Roles reversed: An efficient cobalt-catalyzed electrophilic amination of arylzinc reagents has been achieved. A variety of functionalized arylzincs and N-chloroamines were coupled under mild conditions (see scheme). Both secondary and tertiary arylamines were obtained in moderate to excellent yields. Copyright
Pd(0)/Au(i) redox incompatibilities as revealed by Pd-catalyzed homo-coupling of arylgold(i)-complexes
Weber, Dieter,Gagne, Michel R.
supporting information; experimental part, p. 5172 - 5174 (2011/06/10)
A Pd(ii)-catalyzed homo-coupling of Au(i)-aryls is reported. The reaction is driven by a Pd(0)/Au(i) redox reaction that generates a gold mirror and Pd(ii), and illustrates one of the challenges for developing dual catalytic Au-Pd systems.
Combining Homogeneous Catalysis with Heterogeneous Separation using Tunable Solvent Systems
Blasucci, Vittoria M.,Husain, Zainul A.,Fadhel, Ali Z.,Donaldson, Megan E.,Vyhmeister, Eduardo,Pollet, Pamela,Liotta, Charles L.,Eckert, Charles A.
experimental part, p. 3932 - 3938 (2010/08/04)
Tunable solvent systems couple homogeneous catalytic reactions to heterogeneous separations, thereby combining multiple unit operations into a single step and subsequently reducing waste generation and improving process economics. In addition, tunable solvents can require less energy than traditional separations, such as distillation. We extend the impact of such solvents by reporting on the application of two previously described carbon dioxide tunable solvent systems: polyethylene glycol (PEG)/organic tunable solvents (POTS) and organic/aqueous tunable solvents (OATS). In particular, we studied: (1) the palladium catalyzed carbon-oxygen coupling of 1-bromo-3,5-dimethylbenzene and o-cresol to potassium hydroxide to produce o-tolyl-3,5-xylyl ether and 1-bromo-3,5-di-tert-butylbenzene to potassium hydroxide to produce 3,5-di-tert-butylphenol in PEG400/1,4-dioxane/water and (2) the rhodium-catalyzed hydroformylation of p-methylstyrene in water/ acetonitrile to form 2-(p-tolyl) propanal. In addition, we introduce a novel tunable solvent system based on a modified OATS where propane replaces carbon dioxide. This represents the first use of propane in a tunable solvent system.
Base-catalyzed dehydrogenative Si-o coupling of dihydrosilanes: Silylene protection of diols
Grajewska, Agnieszka,Oestreich, Martin
supporting information; experimental part, p. 2482 - 2484 (2010/11/18)
The direct dehydrogenative coupling of 1,3- and 1,4-diols and dihydrosilanes is efficiently catalyzed by CsO(10 mol%), cleanly affording six- and seven-membered 1,3-dioxo-2-silacycles with dihydrogen as the sole by-product. Conversely, 1,2-diols do not yield the expected 1,3-dioxo-2- silacyclopentanes, essentially forming cyclic disiloxanes instead. Aside from the synthetic convenience, the procedure itself is also useful for straight-forward diol derivatization prior to GLC analysis. Georg Thieme Verlag Stuttgart · New York.
A one-pot, single-solvent process for tandem, catalyzed C-H borylation-Suzuki-Miyaura cross-coupling sequences
Harrisson, Peter,Morris, James,Steel, Patrick G.,Marder, Todd B.
experimental part, p. 147 - 150 (2009/05/30)
Methyl tert-butyl ether is a suitable solvent for iridium-catalyzed C-H borylation followed, in the same pot, by palladium-catalyzed Suzuki-Miyaura cross-coupling sequences, giving high yields of biaryls. Georg Thieme Verlag Stuttgart.
Use of tunable ligands allows for intermolecular Pd-catalyzed C-O bond formation
Vorogushin, Andrei V.,Huang, Xiaohua,Buchwald, Stephen L.
, p. 8146 - 8149 (2007/10/03)
Bulky biaryl phosphine ligands facilitate Pd-catalyzed C-O coupling reactions of aryl halides with primary and secondary alcohols by promoting reductive elimination at the expense of β-hydride elimination. The key to their success is the ability to match the size of the ligand to that of the combination of substrates. The efficient coupling of a number of unactivated aryl chlorides and bromides with cyclic and acyclic secondary alcohols was achieved. This included the coupling of allylic alcohols for the first time in a Pd-catalyzed coupling process.
A novel palladium-catalyzed homocoupling reaction initiated by transmetallation of palladium enolates
Lei, Aiwen,Zhang, Xumu
, p. 2525 - 2528 (2007/10/03)
Palladium-catalyzed homocoupling reaction of aryl boronic acids has been developed using a protocol similar to the well-documented crosscoupling reaction. α-Halocarbonyl compounds are applied to initiate the reaction via oxidative addition to a palladium(0) species. The resulting palladium enolate halide can promote the double transmetallation. Reductive elimination generates the desire homocoupling product.
