- B(C6F5)3-Catalyzed Hydroarylation of Aryl Alkynes for the Synthesis of 1,1-Diaryl and Triaryl Substituted Alkenes
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A new strategy for the synthesis of 1,1-diaryl and triarylsubstituted alkenes has been developed utilizing B(C6F5)3-catalyzed hydroarylation of alkynes with phenols. The method provides a direct route to ortho-alkenylated phenols with both terminal and internal alkynes. The reactions show excellent regioselectivity, and good stereoselectivity was observed for the hydroarylation of internal alkynes. Computational and experimental studies suggest that for the reaction of internal alkynes and phenols, an acid-catalyzed isomerization mechanism involving two tertiary carbonium ion intermediates is responsible for the formation of Z-triaryl substituted alkenes.
- Chen, Hui,Gao, Liuzhou,Liu, Xueting,Wang, Guoqiang,Li, Shuhua
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supporting information
p. 5238 - 5242
(2021/10/19)
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- Deaminative carbonylative coupling of alkylamines with styrenes under transition-metal-free conditions
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A transition-metal-free deaminative carbonylation of alkylamines with styrenes has been developed. The reaction shows good functional group compatibility and various α,β-unsaturated ketones were obtained in moderate to good yields. The alkyl radical generated from Katritzky salts via base-promoted C-N bond cleavage is one of the key intermediates in this reaction. This journal is
- Zhao, Fengqian,Li, Chong-Liang,Wu, Xiao-Feng
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supporting information
p. 9182 - 9185
(2020/08/26)
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- Synthesis of Trifluoromethylated Tetrasubstituted Allenes via Palladium-Catalyzed Carbene Transfer Reaction
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Herein, we report on the palladium-catalyzed synthesis of trifluoromethylated, tetrasubstituted allenes from vinyl bromides and trifluoromethylated diazoalkanes in good to excellent yield. This reaction proceeds via oxidative addition of a Pd(0) complex w
- Koenigs, Rene M.,Pei, Chao,Yang, Zhen
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supporting information
p. 7300 - 7304
(2020/10/02)
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- Synergistic combination of visible-light photo-catalytic electron and energy transfer facilitating multicomponent synthesis of β-functionalized α,α-diarylethylamines
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A synthetic strategy with the visible-light photo-catalytic synergistic combination of electron and energy transfer processes has been developed. The mild reaction conditions allow the radical-radical cross-coupling phenomenon for the multicomponent synthesis of β-arylsulfonyl(diarylphosphinoyl)-α,α-diarylethyl-amines from readily available arylsulfinic acids (diarylphosphine oxides), 1,1-diarylethylenes and arylazides.
- Wu, Yanan,Zhang, Yipin,Jiang, Mingjie,Dong, Xunqing,Jalani, Hitesh B.,Li, Guigen,Lu, Hongjian
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supporting information
p. 6405 - 6408
(2019/06/07)
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- Reactivity of Carbenes in Aqueous Nanomicelles Containing Palladium Nanoparticles
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Palladium nanoparticles ligated with inexpensive triphenylphosphine and amphiphile PS-750-M are suitable for exploring the reactivity of carbenes in aqueous nanomicelles. Nanocatalyst is highly selective for metal-carbene migratory insertion, and micelle
- Duong, Uyen T.,Gade, Amol B.,Plummer, Scott,Gallou, Fabrice,Handa, Sachin
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p. 10963 - 10970
(2019/11/13)
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- Dehydrative Cross-Coupling of 1-Phenylethanol Catalysed by Palladium Nanoparticles Formed in situ under Acidic Conditions
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A dehydrative cross-coupling of 1-phenylethanol catalysed by sugar derived, in situ formed palladium(0) nanoparticles under acidic conditions is realised. The acidic conditions allow for use of alcohols as a feedstock in metal-mediated coupling reactions via their in situ dehydration and subsequent cross-coupling. Extensive analysis of the size and morphology of the palladium nanoparticles formed in situ showed that the zero-valent metal was surrounded by hydrophilic hydroxyl groups. EDX-TEM imaging studies using a prototype silicon drift detector provided insight into the problematic role of molecular oxygen in the system. This increased understanding of the catalyst deactivation allowed for the development of the cross-coupling methodology. A 250-12,000 fold increase in molar efficiency was observed when compared to related two-step protocols that use alternative feedstocks for the palladium-mediated synthesis of stilbenes. This work opens up a new research area in which the active catalyst is formed, stabilised and regenerated by a renewable sugar.
- Camp, Jason E.,Bousfield, Thomas W.,Dunsford, Jay J.,Adams, James,Britton, Joshua,Fay, Michael W.,Angelis-Dimakis, Athanasios
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supporting information
p. 3862 - 3874
(2018/09/29)
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- High-enantioselectivity 1,1-diarylboroalkanes and preparation method thereof
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The invention provides high-enantioselectivity 1,1-diarylboroalkanes and a preparation method thereof, belonging to the technical field of organic synthetic chemistry. The structural general formula of the compounds is disclosed as Formula I. The invention also provides a preparation method of the high-enantioselectivity 1,1-diarylboroalkanes. The method comprises the following steps: carrying out reaction on a copper salt and an alkali under the catalytic action of an alkali to generate a tert-butyl oxy copper intermediate, and reacting with pinacol biborate to generate a copper-boron material, inserting C-C double bonds, and obtaining the hydrogen bononization products under the action of alcohol. The 1,1-diarylboroalkanes have high enantioselectivity; and the high performance liquid chromatography experiment proves that the ee value can reach 90% or above.
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-
Paragraph 0093; 0094; 0095; 0096
(2017/07/21)
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- Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions
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Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.
- Lei, Chuanhu,Yip, Yong Jie,Zhou, Jianrong Steve
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supporting information
p. 6086 - 6089
(2017/05/08)
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- Mn(OAc)3-Mediated Synthesis of 3-Phosphonyldihydrofurans from β-Ketophosphonates and Alkenes
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A new, general method for the synthesis of 3-phosphonyldihydrofuran derivatives has been achieved through Mn(OAc)3-mediated radical cyclization between β-ketophosphonates and alkenes. This transformation allows the direct formation of C-C/C-O bonds and the construction of a dihydrofuran ring in one reaction with operational simplicity and excellent functional-group compatibility.
- Lu, Guozhang,Lin, Binzhou,Gao, Yuzhen,Ying, Jianxi,Tang, Guo,Zhao, Yufen
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p. 724 - 728
(2017/03/21)
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- Branched Arylalkenes from Cinnamates: Selectivity Inversion in Heck Reactions by Carboxylates as Deciduous Directing Groups
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A decarboxylative Mizoroki–Heck coupling of aryl halides with cinnamic acids has been developed in which the carboxylate group directs the arylation into its β-position before being tracelessly removed through protodecarboxylation. In the presence of a copper/palladium catalyst, both electron-rich and electron-deficient aryl bromides and chlorides bearing numerous functionalities were successfully coupled with broadly available cinnamates, with selective formation of 1,1-disubstituted alkenes. This reaction concept, in which the carboxylate acts as a deciduous directing group, ideally complements traditional 1,2-selective Heck reactions of styrenes.
- Tang, Jie,Hackenberger, Dagmar,Goossen, Lukas J.
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supporting information
p. 11296 - 11299
(2016/10/13)
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- Traceless directing group mediated branched selective alkenylation of unbiased arenes
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Owing to the synthetic importance of branched olefinated products, we report palladium catalyzed formation of branched olefins facilitated by a C-H activation based protocol. This involves selective insertion of olefins and subsequent decarboxylation using a completely unbiased benzene ring as the starting precursor. The significance of the protocol has been further highlighted by exhibition of functionality tolerance along with a late-stage modification of the branched olefinated products leading to the formation of other functionalized molecules.
- Agasti, Soumitra,Dey, Aniruddha,Maiti, Debabrata
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supporting information
p. 12191 - 12194
(2016/10/21)
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- Efficient synthesis of polysubstituted olefins using stable palladium nanocatalyst: Applications in synthesis of tamoxifen and isocombretastatin A4
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A phosphine-free stable palladium nanocatalyst was used for an efficient synthesis of polysubstituted olefins from N-tosylhydrazones and aryl iodides. This methodology was successfully utilized in the synthesis of biologically important tamoxifen and isocombretastatin A4. The nanocatalyst was easily recovered and reused without any apparent loss in size and catalytic activity.
- Ganapathy, Dhandapani,Sekar, Govindasamy
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supporting information
p. 3856 - 3859
(2014/08/18)
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- Synthesis of substituted styrenes and 3-vinylphenols using ruthenium-catalyzed ring-closing enyne metathesis
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The synthesis of substituted styrenes 3 and 3-vinylphenols 9 was achieved by ring-closing enyne metathesis (RCEM)/dehydration of 7 and RCEM/tautomerization of 8, respectively. Those methods provide selective access to unique aromatic compounds and solve the problem of regioisomer formation.
- Yoshida, Kazuhiro,Nishii, Kana,Kano, Yuto,Wada, Shiro,Yanagisawa, Akira
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p. 4231 - 4239
(2014/05/20)
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- Palladium/copper-catalyzed oxidative arylation of terminal alkenes with aroyl hydrazides
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An unprecedented oxidative arylation reaction of terminal alkenes with simple aroyl hydrazides has been developed under aerobic conditions for the stereoselective synthesis of 1,2-disubstituted alkenes. A range of aroyl hydrazides underwent palladium/copper-catalyzed oxidative Mizoroki-Heck reaction with terminal alkenes open to air in a 1:1 mixture of dimethyl sulfoxide and acetonitrile to give structurally diverse 1,2-disubstituted alkenes in moderate to excellent yields with excellent regio- and E-selectivity. The reaction tolerated a wide variety of functional groups, such as alkoxy, hydroxy, amino, fluoro, chloro, bromo, cyano, nitro, ester, amide, imide, phosphine oxide, and sulfone groups, and, moreover, molecular oxygen and dimethyl sulfoxide were demonstrated to serve as terminal oxidants. This study provides a useful method for the stereoselective synthesis of 1,2-disubstituted alkenes through direct transformation of the vinylic Ci-H bonds in terminal alkenes. Cross-coupling: An oxidative arylation reaction of terminal alkenes with simple aroyl hydrazides has been developed in the presence of a PdCl2/CuI catalyst under aerobic conditions to give a range of structurally diverse 1,2-disubstituted alkenes in moderate to excellent yields with excellent regio- and E-selectivity (see scheme; r.s.=regioselectivity).
- Zhang, Yong-Gang,Liu, Xiang-Lei,He, Zeng-Yang,Li, Xi-Ming,Kang, Hong-Jian,Tian, Shi-Kai
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supporting information
p. 2765 - 2769
(2014/03/21)
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- Selective arylation and vinylation at the α position of vinylarenes
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In intermolecular Heck reactions of styrene and vinylarenes, the aryl and vinyl groups routinely insert at the β position. However, selective insertion at the α position has been very rare. Herein, we provide a missing piece in the palette of Heck reaction, which gave >20:1 α selectivity. The key to our success is a new ferrocene 1,1′-bisphosphane (dnpf) that carries 1-naphthyl groups. Our mechanistic studies revealed that the high α selectivity is partly attributable to the steric effect of dnpf. The rigid and bulky 1-naphthyl groups of dnpf sterically disfavor β insertion. What the Heck! In intermolecular Heck reactions, insertion at the β position of aromatic olefins is very common, but reversal of the selectivity for selective α insertion has been a longstanding problem. A general method to couple aryl and vinyl triflates with aromatic olefins in >20:1 α selectivity is presented. The key to this successful approach is a new ferrocene bisphosphane with naphthyl groups on the phosphorus atom (see scheme; OTf=triflate). Copyright
- Zou, Yinjun,Qin, Liena,Ren, Xinfeng,Lu, Yunpeng,Li, Yongxin,Zhou, Jianrong
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supporting information
p. 3504 - 3511
(2013/07/05)
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- Construction of polysubstituted olefins through Ni-Catalyzed direct activation of Alkenyl C-O of substituted alkenyl acetates
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(Figure Presented) Reliable companion: For the first time cross-coupling between alkenyl acetates and arylboroxines/PhZnCl has been developed via Ni catalysis. Alkenyl acetates could be well-differ-entiated from aryl acetates (see scheme). This reliable method provides a convenient pathway to construct polysubstituted styrene derivatives.
- Sun, Chang-Liang,Yang, Wang,Xiao, Zhou,Wu, Zhen-Hua,Li, Bi-Jie,Guan, Bing-Tao,Shi, Zhang-Jie
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supporting information; experimental part
p. 5844 - 5847
(2010/09/03)
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- Aqueous sodium hydroxide promoted cross-coupling reactions of alkenyltrialkoxysilanes under ligand-free conditions
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(Chemical Equation Presented) Fluoride-free cross-coupling reactions of alkenyltrialkoxysilanes with aryl iodides, bromides, and chlorides are performed on water using sodium hydroxide as activator at 120 °C under normal or microwave heating. This process occurs in the presence of Pd(OAc)2 or 4-hydroxyacetophenone oxime-derived palladacycle 1 as precatalysts under ligand-free conditions with low Pd loadings (0.01-1 mol %) and using tetra-n-butylammonium bromide as additive. Different commercially available vinylalkoxylsilanes can be cross-coupled under these reaction conditions to the corresponding styrenes, the best substrates being vinyltrimethoxy- or vinyltriethoxysilane. Alkenyltriethoxysilanes, prepared by Wilkinson-catalyzed hydrosilylation of alkynes with triethoxysilane, are stereospecifically arylated with aryl and vinyl halides under microwave irradiation in moderate to high β/α regioselectivity affording unsymmetrical stilbenes, alkenylbenzenes, and conjugate dienes, respectively. This simple procedure allows the palladium recycling from the aqueous phase during three runs by extractive separation of the products, which contain very low levels of Pd (21-27.5 ppm for an aryl iodide and up to 76 ppm for a bromide).
- Alacid, Emilio,Najera, Carmen
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p. 2315 - 2322
(2008/09/19)
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- Metal-free hydroarylation of alkynes: A very convenient, simple procedure for substituted arylalkenes
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Hydroarylation of aryl-substituted alkynes with simple and substituted arenes was conducted in the presence of trifluoroacetic acid in dichloromethane without any metal catalysts or additives. Electron-rich arenes coupled with aryl-substituted alkynes to give 1,1-diarylalkenes in good to high yields. Georg Thieme Verlag Stuttgart.
- Rahman, Md. Ataur,Ogawa, Osamu,Oyamada, Juzo,Kitamura, Tsugio
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experimental part
p. 3755 - 3760
(2009/06/06)
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- FeCl3-catalyzed alkenylation of simple arenes with aryl-substituted alkynes
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An addition of electron-rich arenes to aryl-substituted alkynes to form 1,1-diaryl alkenes is carried out in the presence of FeCl3 as catalyst under mild conditions.
- Li, Ruoshi,Wang, Sunewang R.,Lu, Wenjun
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p. 2219 - 2222
(2008/02/05)
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- Direct synthesis of 1,1-diarylalkenes from alkenyl phosphates via nickel(0)-catalysed Suzuki-Miyaura coupling
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A combination of Ni(COD)2 and PCy3 promotes effectively the Suzuki-Miyaura cross coupling of 1-arylalkenyl phosphates with aryl boronic acids with yields attaining 99%. The Royal Society of Chemistry 2006.
- Hansen, Anders L.,Ebran, Jean-Philippe,Gogsig, Thomas M.,Skrydstrup, Troels
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p. 4137 - 4139
(2007/10/03)
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- An efficient Negishi cross-coupling reaction catalyzed by nickel(II) and diethyl phosphite
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A combination of diethyl phosphite-DMAP and Ni(II) salts forms a very effective catalytic system for the cross-coupling reactions of arylzinc halides with aryl, heteroaryl, and alkenyl bromides, chlorides, triflates, and nonaflates. The choice of solvent is quite important and the mixture of THF-N-ethylpyrrolidinone (NEP) (8:1) was found to be optimal. The reaction usually requires only 0.05 mol % of NiCl2 or Ni(acac)2 as catalyst and proceeds at room temperature within 1-48 h.
- Gavryushin, Andrei,Kofink, Christiane,Manolikakes, Georg,Knochel, Paul
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p. 7521 - 7533
(2007/10/03)
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- Enantiodifferentiation of a silane and the analogous hydrocarbon by the dirhodium method-silane...dirhodium complex interaction
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Chiral silane 1 was enantiodifferentiated by recording NMR spectra in the presence of the chiral dirhodium complex Rh2(II) [(R) - (+) - MTPA4] (Rh*). This is the first report of direct chiral recognition by spec
- Diaz Gomez, Edison,Albert, Dieter,Mattiza, Jens,Duddeck, Helmut,Chojnowski, Julian,Cypryk, Marek
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p. 1743 - 1748
(2007/10/03)
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- Gold(I)-catalyzed oxidative cleavage of a C-C double bond in water
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Oxidative cleavage of the C=C bond to afford ketone or aldehyde products with tert-butyl hydrogenperoxide (TBHP) as the oxidant can be catalyzed by AuCl with neocuproine (1) in water.
- Xing, Dong,Guan, Bingtao,Cai, Guixin,Fang, Zhao,Yang, Liping,Shi, Zhangjie
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p. 693 - 696
(2007/10/03)
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- Recyclable ligand-free mesoporous heterogeneous Pd catalysts for Heck coupling
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Ligand-free Pd-MCM41 catalysts are highly active in the Heck coupling of bromoarenes including deactivated bromo derivatives to give coupled products in high yields with high selectivities without the need to exclude air or moisture. The catalyst samples exhibit unprecedented stability among heterogeneous catalysts and can be reused at least 20 times to achieve complete conversion without any additional activation treatment.
- Papp, Attila,Galbács, Gábor,Molnár, árpád
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p. 7725 - 7728
(2007/10/03)
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- PtBr2-catalyzed consecutive enyne metathesis-aromatization of 1-(1-methoxy-but-3-enyl)-2-(1-alkynyl)benzenes: Dual role of the Pt catalyst
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(Chemical Equation Presented) 1,7-Enynes 1, connected through an aromatic ring and bearing a leaving methoxy group at the 4-position, underwent the PtBr2-catalyzed enyne metathesis followed by aromatization in one pot to afford vinyl naphthalen
- Bajracharya, Gan B.,Nakamura, Itaru,Yamamoto, Yoshinori
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p. 892 - 897
(2007/10/03)
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- Synthesis of polysubstituted alkenes by Heck vinylation or Suzuki cross-coupling reactions in the presence of a tetraphosphane-palladium catalyst
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Through the use of [PdCl(C3H5)]2/cis,cis,cis-1,2,3, 4-tetrakis[(diphenylphosphanyl)methyl]cyclopentane as a catalyst, a range of vinyl bromides undergo Suzuki cross-couplings with arylboronic acids in good yields. Furthermore, the catalyst can be used at low loadings, even for reactions of sterically hindered substrates. Mediated by this catalyst, stilbene and 1,1-diphenylethylene undergo Heck reactions with aryl halides to give triarylethylene derivatives. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Berthiol, Florian,Doucet, Henri,Santelli, Maurice
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p. 1091 - 1096
(2007/10/03)
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- An unusual, DDQ-promoted oxidative rearrangement of 9,9-disubstituted 1,4,5,8-tetrahydro-4a,8a-methanonaphthalenes
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The action of excess DDQ on 1,4,5,8-tetrahydro-4a,8a-methanonaphthalenes bearing a methyl group and one other substituent (cyclopropyl, methyl, phenyl) at the 9 position resulted in a peculiar oxidative rearrangement to 1-vinylnaphthalene derivatives. Two closely related mechanisms, both of which involve a 1,5-sigmatropic shift of the one-carbon bridge (Berson-Willcott rearrangement), are considered for this novel process.
- Barasz, Jonah A.,Ghaffari, Ali H.,Otte, Douglas A.,Thamattoor, Dasan M.
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- Electrophilic Alkenylation of Arometics with Phenylacetylene over Zeolite HSZ-360
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Aromatic compounds react with phenylacetylene in the presence of zeolite HSZ-360 affording 1,1-diarylethylenes 3 in good to excellent yields and selectivities.
- Sartori, Giovanni,Bigi, Franca,Pastorio, Andrea,Porta, Cecilia,Arienti, Attilio,et al.
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p. 9177 - 9180
(2007/10/02)
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- On the regioselectivity of palladium catalyzed cross-coupling reactions of alkenylsilanes: participation of β-cationic organosilicate-palladium species during the transmetallation
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The cross-coupling reaction promoted by a palladium catalyst and fluoride salt of 1--1-phenylethene (1) with substituted aryl iodides gave the unexpected cine-substitution products (E)-1-aryl-2-phenylethenes (3) along with the normal ipso-substitution product 1-aryl-1-phenylethene (2).The product ratios were strongly dependent on the electronic nature of the substituent on aryl iodides: ipso-substitution products (2) were favoured by an electron-withdrawing substituent, and cine-substitution products (3) by an electron-donating substituent.On the basis of these observations, the following mechanism of transmetallation of alkenyl(fluoro)silicates with arylpalladium is proposed: electrophilic attack of an arylpalladium complex on the olefinic α-carbon of an alkenyl(fluoro)silicate produces a β-cationic organosilicate-palladium species which then transfers the alkenyl group from silicon to the palladium complex. Key words: Silane; Palladium; Transmetallation; Regioselectivity
- Hatanaka, Yasuo,Goda, Ken-ichi,Hiyama, Tamejiro
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- 1,10-Phenanthroline Derivatives: A New Ligand Class in the Heck Reaction. Mechanistic Aspects
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Mechanistic studies concerning the use of 1,10-phenanthroline derivatives as palladium ligands in the Heck reaction are described.The work is focused on the steering factors for the coordination of unsaturated systems onto palladium(0) and palladium(II) complexes.
- Cabri, Walter,Candiani, Ilaria,Bedeschi, Angelo,Santi, Roberto
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p. 7421 - 7426
(2007/10/02)
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- Palladium-Catalyzed Arylation of Unsymmetrical Olefins. Bidentate Phosphine Ligand Controlled Regioselectivity
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The palladium-catalyzed arylation of several unsymmetrical olefins by aryl triflates in the presence of bidentate phosphine ligands is described.The use of these ligands increases the influence that electronic factors have in determining the regioselectivity of the reaction.The catalyst performances allow a revisiting of the scheme that describes the regioselectivity outcome in Heck-type reactions.Furthermore, a general mechanism for the palladium-catalyzed arylation of olefins is proposed.
- Cabri, Walter,Candiani, Ilaria,Bedeschi, Angelo,Santi, Roberto
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p. 3558 - 3563
(2007/10/02)
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- Triplet State of α-Naphthylethylene Derivatives. Structural Effects on the Equilibrium between Planar and Perpendicular Triplet Conformations
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The properties of the triplet state of a series of 1-(α-naphthyl)ethylene derivatives have been studied by laser flash photolysis.The geometry of the triplet state has been determined from the T-T absorption spectra, the lifetime values, and the quenching rate constants by oxygen, stilbene, and ferrocene.The triplet state can be either planar (nontwisted double bond), when the ethylenic moiety is inserted into a small ring, or perpendicular (double bond twisted by 90 deg), when the planar geometry is disfavored by a strong steric hinderance.However, in most cases, there is a fast equilibrium between the planar and perpendicular triplets.These two geometries are very close in energy and therefore the equilibrium can be greatly modified by small changes in the molecular structure such as an alkyl substitution.By comparison of the triplet state of 1-(α-naphthyl)-1-phenylethylene with that of other 1-aryl-1-phenylethylenes, an experimental correlation is found between the percentage of planar triplet and the triplet energy of the aryl group.
- Lazare, Sylvain,Bonneau, Roland,Lapouyade, Rene
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