- Sequential reactions of trimethylstannyl anions with vinyl chlorides and dichlorides by the SRN1 mechanism followed by palladium-catalyzed cross-coupling processes
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The reactions of trimethylstannyl ions (Me3Sn-) with vinyl chlorides in liquid ammonia give good yields of vinylstannanes. Some of them react in the dark, and others need light stimulation to react. The fact that these reactions are inhibited by radical and radical anion traps shows that they occur by the SRN1 mechanism. When the reaction takes place with 1,1-dichloro-1-alkenes, monosubstitution reduced products are formed in an E/Z mixture. The efficient synthesis of triarylolefins by Pd(0)-catalyzed cross-coupling reactions of vinylstannanes with several iodoarenes is reported. Similar yields were obtained in one-pot-type reactions.
- Corsico, Eduardo F.,Rossi, Roberto A.
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Read Online
- Pd-Catalyzed Coupling of N-Tosylhydrazones with Benzylic Phosphates: Toward the Synthesis of Di- or Tri-Substituted Alkenes
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This study shows that various di- and tri-substituted alkenes with high chemoselectivity were obtained in good to high yields by coupling N-tosylhydrazones (NTHs) with benzylic phosphates as electrophilic partners. The obtained new catalytic system consis
- Zhang, Kena,Provot, Olivier,Alami, Mouad,Tran, Christine,Hamze, Abdallah
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p. 1249 - 1261
(2022/02/07)
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- Immobilized Pd on Eggshell Membrane: A powerful and recyclable catalyst for Suzuki and Heck cross-coupling reactions in water
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A stable heterogeneous palladium catalysts, the waste eggshell membrane (ESM) anchored Pd complex, was synthesized by a simple and green technique. The catalyst obtained can display an outstanding catalytic activity for Suzuki and Heck coupling reactions in water media. The reactions of various aryl halides with aryl boronic acids and terminal alkenes provided the corresponding products in moderate to excellent yields. More importantly, this novel and efficient catalyst with high stability can be easily reused for at least twelve times with no decrease of the catalytic activity, performing an endurable and wide tolerance of the substrates. Facile synthesis, high catalytic activity, and recyclability make these catalysts interesting for further studies.
- Wu, Shang,Jiang, Hongyan,Zhang, Hong,Zhao, Lianbiao,Yuan, Peilin,Zhang, Ying,Su, Qiong,Wang, Yanbin,Wu, Lan,Yang, Quanlu
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- Microwave-assisted periselective annulation of triarylphosphenes with aldehydes and ketones
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The reaction of diazo(aryl)methyl(diaryl)phosphine oxides with aldehydes and ketones generates benzo-δ-phosphinolactones in low to good yields with 1,1-diarylalk-1-enes as byproducts under microwave irradiation. Diazo(aryl)methyl(diaryl)phosphine oxides first undergo a Wolff rearrangement to form diaryl(aryl)phosphenes, which further react with aldehydes and ketones to afford benzo-δ-phosphinolactones and β-phosphinolactones. The latter are unstable under heating and fragment into the corresponding 1,1-diarylalk-1-enes and arylphosphine dioxides under reaction conditions. The arylphosphine dioxides become arylphosphonic acids during workup. The periselectivity in the annulation shows that the reaction of diaryl(aryl)phosphenes with most aldehydes and ketones favors phosphene phenyl participation in (4 + 2) annulation(2 + 2) annulation. This journal is
- Du, Changle,Fu, Xingyang,Fu, Zhicheng,Luo, Yun,Xu, Jiaxi
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p. 9526 - 9537
(2020/12/15)
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- Polysubstituted ethylene compound as well as preparation method and application thereof
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The invention discloses a polysubstituted ethylene compound as well as a preparation method and application thereof. The invention particularly discloses a preparation method of a polysubstituted ethylene compound as shown in a formula III, which comprises the following step: in an organic solvent, carrying out reaction as shown in the specification on a compound as shown in a formula I and a compound as shown in a formula II in the presence of a palladium catalyst, a phosphine ligand and alkali to obtain the polysubstituted ethylene compound as shown in the formula III. The preparation methodcan be suitable for various types of substrates, and the configuration of double bonds is controllable.
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Paragraph 0125-0129; 0245-0249
(2020/12/30)
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- Sunlight-Driven Synthesis of Triarylethylenes (TAEs) via Metal-Free Mizoroki–Heck-Type Coupling
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A protocol for the preparation of substituted triarylethylenes (TAEs) was developed by using arylazo sulfones as substrates in the presence of 1,1-diarylethylenes. The process took place efficiently in the absence of any (photo)catalyst upon exposure of the reaction mixture to (simulated) sunlight.
- Onuigbo, Louis,Raviola, Carlotta,Di Fonzo, Andrea,Protti, Stefano,Fagnoni, Maurizio
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p. 5297 - 5303
(2018/09/14)
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- Electrochemical Aziridination by Alkene Activation Using a Sulfamate as the Nitrogen Source
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The first direct aziridination of triaryl-substituted alkenes was achieved by means of an electrochemical process that could extend to multisubstituted styrenes. Specifically, hexafluoroisopropanol sulfamate was used as a nucleophilic nitrogen source. Mechanistic experiments suggest that this electrochemical process proceeds by stepwise formation of two C?N bonds through reactions between cationic carbon species and the sulfamate.
- Li, Jin,Huang, Wenhao,Chen, Jingzhi,He, Lingfeng,Cheng, Xu,Li, Guigen
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supporting information
p. 5695 - 5698
(2018/04/30)
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- Silver sequestration of halides for the activation of Pd(OAc)2 catalyzed Mizoroki-Heck reaction of 1,1 and 1,2 - Disubstituted alkenes
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A ligand free catalytic system consisting of Pd(OAc)2 (cat) and stoichiometric quantities of silver salts, AgOAc or AgBF4, exhibit high efficiency in the Mizoroki-Heck arylation, transforming aryl iodides and 1,1 as well as 1,2 disubstituted alkenes into 1,1,2 – trisubstituted aryl alkenes in excellent yields in very short reaction times.
- Bangar, Pronnoy G.,Jawalkar, Priyanka R.,Dumbre, Swapnil R.,Patil, Dharmaraj J.,Iyer, Suresh
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- Electron transfer-induced coupling of haloarenes to styrenes and 1,1-diphenylethenes triggered by diketopiperazines and potassium tert-butoxide
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The coupling of haloarenes to styrenes and 1,1-diarylethenes has been achieved with potassium tert-butoxide in the presence of N,N'-dialkyldiketopiperazines. In contrast to previously reported reactions where phenanthroline has been used to mediate the reactions, the use of diketopiperazines can lead to either 1,1,2-triarylethenes or 1,1,2-triarylethanes, depending on the conditions used.
- Doni, Eswararao,Zhou, Shengze,Murphy, John A.
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p. 1755 - 1774
(2015/02/05)
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- Biopolymer-metal complex wool-Pd as a highly active heterogeneous catalyst for Heck reaction in aqueous media
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Heterogeneous palladium catalysts, a biopolymer complex wool-Pd, have been applied in water-mediated coupling reactions of aryl bromides without assistance of any phosphine ligands. The catalyst was characterized by XPS, ICP. The results showed that aryl bromides could carry out the coupling reaction with a variety of alkenes at 80 °C, in aqueous media under atmospheric condition. More importantly, the cheap catalyst is stable, which shows negligible metal leaching, and retain good activity for at least ten successive runs without any additional activation treatment. This approach would be very useful from a practical viewpoint.
- Wu, Shang,Ma, Hengchang,Jia, Xiaojie,Zhong, Yunmei,Lei, Ziqiang
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experimental part
p. 250 - 256
(2011/02/27)
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- Direct arylation of alkenes with aryl iodides/bromides through an organocatalytic radical process
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A radical addition: A KOtBu-complex-promoted radical arylation of polysubstituted alkenes with aryl iodides/bromides proceeds in high efficiency (see scheme). Benzofuran derivatives are also produced starting from readily available allyl 2-iodophenyl ethers. Copyright
- Sun, Chang-Liang,Gu, Yi-Fan,Wang, Bin,Shi, Zhang-Jie
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supporting information; experimental part
p. 10844 - 10847
(2011/10/31)
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- Triazole-functionalized N-heterocyclic carbene complexes of palladium and platinum and efficient aqueous Suzuki-Miyaura coupling reaction
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Imidazolium salts bearing triazole groups are synthesized via a copper catalyzed click reaction, and the silver, palladium, and platinum complexes of their N-heterocyclic carbenes are studied. [Ag4(L1) 4](PF6)4, [Pd(L1)Cl](PF6), [Pt(L1)Cl](PF6) (L1=3-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-1- (pyrimidin-2-yl)-1H-imidazolylidene), [Pd2(L2)2Cl 2](PF6)2, and [Pd(L2)2](PF 6)2 (L2=1-butyl-3-((1-(pyridin-2-yl)-1H-1,2,3-triazol-4- yl)methyl) imidazolylidene) have been synthesized and fully characterized by NMR, elemental analysis, and X-ray crystallography. The silver complex [Ag 4(L1)4](PF6)4 consists of a Ag 4 zigzag chain. The complexes [Pd(L1)Cl](PF6) and [Pt(L1)Cl](PF6), containing a nonsymmetrical NCN' pincer ligand, are square planar with a chloride trans to the carbene donor. [Pd 2(L2)2Cl2](PF6)2 consists of two palladium centers with CN2Cl coordination mode, whereas the palladium in [Pd(L2)2](PF6)2 is surrounded by two carbene and two triazole groups with two uncoordinated pyridines. The palladium compounds are highly active for Suzuki-Miyaura cross coupling reactions of aryl bromides and 1,1-dibromo-1-alkenes in neat water under an air atmosphere.
- Gu, Shaojin,Xu, Hui,Zhang, Na,Chen, Wanzhi
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experimental part
p. 1677 - 1686
(2011/08/05)
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- Formation and Reactivity of ?-Radical Cation Intermediates in the C-C Coupling Reaction of Phenyldiazomethanes by One-Electron Oxidation
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One-electron oxidation of phenyldiazomethanes afforded cis-stilbene predominantly.The reaction was independent of the oxidation methods, e.g., electrolysis, copper(II), triarylaminium salts, or photosensitized one-electron oxidtions.The C-C coupling reaction was retarded by introducing α-substituents on phenyldiazomethanes.The ESR spectra of diazoalkane radical cations could be obtained during the electrolysis at low temperature and the resulting spectra revealed their unique electronic structure as ?-radicals for most cases.When a bulky tert-butyl group was substituted, the corresponding ?-radical cation was observed, but the C-C coupling reaction did not occur.The novel HOMO-LUMO switching by one-electron removal from the HOMO ?-orbital of diazomethane is explained by the interaction of phenyl group with the C-N-N ?-radical moiety.The C-C coupling reaction proceeds via facile cycloaddition between the diazomethane and ?-radical cation, and the preferential formation of cis-olefins is based on the secondary orbital interaction between the two phenyl groups.The structure and the stability of radical cation intermediates are rationalized on the basis of ab initio calculations.
- Ishiguro, Katsuya,Ikeda, Masatoshi,Sawaki, Yasuhiko
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p. 3057 - 3066
(2007/10/02)
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- FROM THIIRANES TO THIOCARBONYL S-SULFIDES; RECENT RESULTS
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A novel nucleophilic catalysis for the desulfurization of thiiranes is described.Triphenylthiirane is quantitatively converted to triphenylethylene by some molpercent sodium thiophenoxide or other thiolates in DMSO at 35 deg C.A rapid initial reaction is retarded by the eliminated sulfur leading to a pseudo-first-order reaction under quasi-stationary conditions.The suggested mechanism is based on structure-rate relationships. - The thiolate-catalyzed reaction of cis-2,3-diphenylthiirane is exceptional in furnishing equimolar quantities of cis-stilbene and 3,4,6,7-tetraphenyl-1,2,5-trithiepane (2 diastereoisomers with bilateral symmetry); mechanistic implications - thiolate attack on sulfur or C-atom of thiirane - are discussed. - Desulfurization of 2,2-diphenylthiirane by thiobenzophenone or other thioketones gives access to thiocarbonyl S-sulfides ("thiosulfines") which are intercepted by 1,3-cycloadditions to activated acetylenes or to thiones.
- Huisgen, Rolf
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