- Coupling alkylation of (E)-α-selanylvinylic zirconium compounds to give trisubstituted alkenes
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Hydrozirconation of internal acetylenic selenides afforded 1, 1- bimetalloalkenes, (E)-α-selanylvinylzirconium, which can undergo sequential cross coupling reaction to form two carbon-carbon bonds in the same olefinic carbon leading to trisubstituted alke
- Sun,Huang
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- A new insight into the push-pull effect of substituents via the stilbene-like model compounds
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In this paper, authors report on 1-pyridyl-2-arylethenes, 1-furyl-2-arylethylenes, 1,2-diphenylpropylenes and substituted cinnamyl anilines as stilbene-like model compounds to investigate the factors dominating the push-pull effect of substituents via usi
- Cao, Chaotun,Cao, Chenzhong,Zeng, Zhao
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- 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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- Method for synthesizing alkyl olefin through coupling of double-bond carbon-hydrogen bond and saturated carbon-hydrogen bond
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The invention discloses a method for synthesizing alkyl olefin through coupling of a double-bond carbon-hydrogen bond and a saturated carbon-hydrogen bond. According to to the method, one-pot reactionis implemented on olefin and sulfoxide in the presence of ferric salt and hydrogen peroxide to generate alkyl olefin; in the method, sulfoxide is simultaneously used as a hydrocarbylation reagent anda solvent of olefin, and a reaction product is alkyl olefin from sulfoxide alkyl coupled with olefin carbon atoms, so that an olefin carbon chain is increased; the reaction conditions are mild, the selectivity is good, the yield is high, and industrial production is facilitated.
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Paragraph 0060-0069; 0095
(2021/02/10)
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- Method for hydrocarbylation synthesis of trisubstituted and tetrasubstituted olefins from non-terminal olefins
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The invention discloses a method for hydrocarbylation synthesis of trisubstituted and tetrasubstituted olefins from non-terminal olefins, wherein the method comprises the steps: carrying out hydrocarbylation reaction on the non-terminal olefins and sulfoxide in the presence of ferric salt and hydrogen peroxide, carrying out one-pot reaction on disubstituted non-terminal olefins to generate the trisubstituted olefins, and carrying out one-pot reaction on the trisubstituted non-terminal olefins to generate the tetrasubstituted olefins. In the method, sulfoxide is simultaneously used as a hydrocarbylation reagent and a solvent of olefins, and one more hydrocarbyl substituent is added to a reaction product compared with a double-bond carbon atom of a reactant, so that an olefin carbon chain isincreased; the reaction conditions are mild, the selectivity is good, the yield is high, and industrial production is facilitated.
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Paragraph 0054-0063; 0067-0069
(2021/02/06)
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- Synthesis of new adamantyl-imine palladium(II) complexes and their application in Mizoroki-Heck and Suzuki-Miyaura C[sbnd]C cross-coupling reactions
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Improving carbon–carbon cross-coupling reactions is an ongoing process and finding the most versatile and stable catalyst precursors has been of great interest. Ligand design has been proven to be important since it is responsible for providing electron density and steric saturation around the metal centre, thus contributing towards the stereo-electronic properties. The adamantyl moiety has been used to generate highly bulky and electron-rich ligands for application in palladium-catalysed cross-coupling reactions. Accordingly, we have prepared some Schiff-base adamantyl ligands (L1-L3) and complexed them with [PdCl2(MeCN)2] to afford the (pre)catalysts C1-C3, which were successfully applied in Mizoroki-Heck and Suzuki-Miyaura carbon–carbon cross-coupling reactions. The cross-coupling reaction products were obtained in good yields using 0.5 mol % Pd catalyst loading. C2 and C3 showed remarkable activity in the Mizoroki-Heck coupling reactions involving substrates with substituents on the olefin and aryl halide (including 4-Cl, 4-CH3, -CO2Me and -CO2Et). We also, observed that the Suzuki-Miyaura cross-coupling system was active towards challenging activated and deactivated aryl chlorides, with to up 70% conversions recorded. The mercury poisoning tests conducted revealed that the catalysts act as homogenous molecular active species in the Mizoroki-Heck reactions and act as both homogenous and heterogeneous catalysts in the Suzuki-Miyaura cross-coupling reactions.
- Makhubela, Banothile C. E.,Matsheku, Asanda C.,Maumela, Munaka C.
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- Heteroleptic Copper-Based Complexes for Energy-Transfer Processes: E → Z Isomerization and Tandem Photocatalytic Sequences
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Energy-transfer processes involving copper complexes are rare. Using an optimized heteroleptic copper complex, Cu(bphen)(XantPhos)BF4, photosensitized E → Z isomerization of olefins is demonstrated. The XantPhos ligand afforded sensitizers with improved catalyst stability, while the bphen ligand lengthened the excited-state lifetime. A series of 25 di- and trisubstituted alkenes underwent photoisomerization, including macrocycles and 1,3-enynes. Cu(bphen)(XantPhos)BF4 could also be employed in a tandem ATRA/photoisomerization process employing arylsulfonyl chlorides, an example of photoisomerization with halide-substituted olefins.
- Cruché, Corentin,Neiderer, William,Collins, Shawn K.
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p. 8829 - 8836
(2021/07/28)
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- Recyclable and reusable PdCl2(PPh3)2/PEG-400/H2O system for the hydrophenylation of alkynes with sodium tetraphenylborate
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A stable and efficient PdCl2(PPh3)2/PEG-400/H2O catalytic system for the hydrophenylation reaction of alkynes has been developed. In the presence of 3 mol% PdCl2(PPh3)2 and 2 equiv. of HOAc, the hydrophenylation of both terminal and internal alkynes with sodium tetraphenylborate proceeded smoothly in a mixture of PEG-400 and water at room temperature or 50 °C to afford a variety of phenyl-substituted alkenes in moderate to high yields. The isolation of the products was easily performed by extraction with petroleum ether, and the PdCl2(PPh3)2/PEG-400/H2O system could be readily recycled and reused six times without apparent loss of catalytic activity.
- Liu, Rong,Zhang, Tingli,Huang, Bin,Cai, Mingzhong
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p. 172 - 178
(2020/07/04)
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- Regioselective Synthesis of α-Functional Stilbenes via Precise Control of Rapid cis- trans Isomerization in Flow
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The rapid cis-trans isomerization of α-anionic stilbene was regioselectively controlled by using flow microreactors, and its reaction with various electrophiles was conducted. The reaction time was precisely controlled within milliseconds to seconds at -50 °C to selectively give the cis- or trans-isomer in high yields. This synthetic method in flow was well-applied to synthesize precursors of commercial drug compound, (E)- and (Z)-tamoxifen with high regioselectivity and productivity.
- Lee, Hyune-Jea,Yonekura, Yuya,Kim, Nayoung,Yoshida, Jun-Ichi,Kim, Heejin
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p. 2904 - 2910
(2021/05/05)
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- METHODS OF ARENE ALKENYLATION
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The present disclosure provides for a rhodium-catalyzed oxidative arene alkenylation from arenes and styrenes to prepare stilbene and stilbene derivatives. For example, the present disclosure provides for method of making arenes or substituted arenes, in particular stilbene and stilbene derivatives, from a reaction of an optionally substituted arene and/or optionally substituted styrene. The reaction includes a Rh catalyst or Rh pre-catalyst material and an oxidant, where the Rh catalyst or Rh catalyst formed Rh pre-catalyst material selectively functionalizes CH bond on the arene compound (e.g., benzene or substituted benzene).
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Page/Page column 18; 42; 51
(2021/11/26)
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- Iron Catalyzed Isomerization of α-Alkyl Styrenes to Access Trisubstituted Alkenes
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Stereoselective isomerization of α-alkyl styrenes is accomplished using a new iron catalyst supported by phosphine-pyridine-oxazoline (PPO) ligand. The protocol provides an atom-efficient and operationally simple approach to trisubstituted alkenes in high
- Xu, Songgen,Liu, Guixia,Huang, Zheng
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p. 585 - 589
(2021/02/01)
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- Highly Stereoselective Positional Isomerization of Styrenes via Acid-Catalyzed Carbocation Mechanism
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The first transition metal-free highly stereoselective positional isomerization of various α-alkyl styrenes through a carbocation mechanism triggered strategy is developed by using Al(OTf)3 as a hidden Br?nsted acid catalyst, which provides facile access to value-added acyclic tri- and tetra-substituted alkenes in good yields with high stereoselectivity under mild conditions. The practicality of this protocol is further highlighted by the gram-scale synthesis, high stereoselectivity, good functional group tolerance, and simple operation. Mechanistic studies support that Al(OTf)3 acts as a hidden Br?nsted acid catalyst and a carbocation intermediate is formed.
- Hu, Xiao-Si,He, Jun-Xiong,Zhang, Ying,Zhou, Jian,Yu, Jin-Sheng
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supporting information
p. 2227 - 2233
(2021/06/28)
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- Cobalt-Catalyzed Hydroboration of Terminal and Internal Alkynes
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A novel methodology to access synthetically versatile vinylboronic esters through a ligand-controlled cobalt-catalyzed hydroboration of terminal and internal alkynes is reported. The approach relies on the in situ reduction of Co(II) by H-BPin in the presence of bisphosphine ligands generating catalytically active Co(I) hydride complexes. This procedure avoids the use of stoichiometric amounts of base, and no boron-containing byproducts are generated which is translated into high functional group tolerance and atom economy.
- González, María J.,Bauer, Felix,Breit, Bernhard
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supporting information
p. 8199 - 8203
(2021/10/25)
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- Remote sp2C-H Carboxylation via Catalytic 1,4-Ni Migration with CO2
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A remote catalytic reductive sp2 C-H carboxylation of arenes with CO2 (1 bar) via 1,4-Ni migration is disclosed. This protocol constitutes the first catalytic 1,4-Ni migration reported to date, thus offering new vistas in the Ni-catalyzed reductive coupling arena while providing an unconventional new platform for incorporating electrophilic sites at remote sp2 C-H linkages.
- B?rjesson, Marino,Duan, Yaya,Janssen-Müller, Daniel,Martin, Ruben,Sahoo, Basudev,Wang, Xueqiang
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supporting information
p. 16234 - 16239
(2020/10/09)
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- Nickel-Catalyzed Allylmethylation of Alkynes with Allylic Alcohols and AlMe3: Facile Access to Skipped Dienes and Trienes
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We present herein an unprecedented allylative dicarbofunctionalization of alkynes with allylic alcohols. This simple catalytic procedure utilizes commercially available Ni(COD)2, triphenylphosphine, and inexpensive reagents, and delivers valuable skipped dienes and trienes with an all-carbon tetrasubstituted alkene unit in a highly stereoselective fashion. Preliminary mechanistic studies support the reaction pathway of allylnickelation followed by transmetalation in this dicarbofunctionalization of alkynes.
- Li, Jincan,Li, Wanfang,Yu, Shun,Zhao, Yu
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p. 14404 - 14408
(2020/07/04)
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- Promising new catalytic properties of a Co (II)-carboxamide complex and its derived Co3O4 nanoparticles for the Mizoroki-Heck and the Epoxidation reactions
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The new Co(II) - carboxamide complex (1) and Co3O4 nanoparticles (2), by way of thermal decomposition of (1) have been efficiently synthesised in the environment-friendly. X-ray diffraction reveals a slightly distorted octahedral coordination of cobalt (four nitrogens and two oxygens) in (1) and regular octahedral or tetrahedral ones (oxygens only) in (2). The investigation of (1) and (2) in the Mizoroki-Heck and epoxidation of alkens reactions showed them both to be powerful, green and inexpensive catalysts.
- Kiani, Mahsa,Bagherzadeh, Mojtaba,Meghdadi, Soraia,Fadaei-Tirani, Farzaneh,Babaie, Maryam,Schenk-Jo?, Kurt
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- Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes
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Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers of trisubstituted alkenes (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization of 1,1-disubstituted alkenes can serve as an alternative approach to trisubstituted alkenes, but it remains underdeveloped owing to issues relating to reaction efficiency and stereoselectivity. Here we show that a novel cobalt catalyst can overcome these challenges to provide an efficient and stereoselective access to a broad range of trisubstituted alkenes. This protocol is compatible with both mono- and dienes and exhibits a good functional group tolerance and scalability. Moreover, it has proven to be a useful tool to construct organic luminophores and a deuterated trisubstituted alkene. A preliminary study of the mechanism suggests that a cobalt-hydride pathway is involved in the reaction. The high stereoselectivity of the reaction is attributed to both a π-πstacking effect and the steric hindrance between substrate and catalyst.
- Zhang, Sheng,Bedi, Deepika,Cheng, Lu,Unruh, Daniel K.,Li, Guigen,Findlater, Michael
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p. 8910 - 8917
(2020/12/23)
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- Synthesis of Stilbenes by Rhodium-Catalyzed Aerobic Alkenylation of Arenes via C-H Activation
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Arene alkenylation is commonly achieved by late transition metal-mediated C(sp2)-C(sp2) cross-coupling, but this strategy typically requires prefunctionalized substrates (e.g., with halides or pseudohalides) and/or the presence of a directing group on the arene. Transition metal-mediated arene C-H activation and alkenylation offers an alternative method to functionalize arene substrates. Herein, we report a rhodium-catalyzed oxidative arene alkenylation from arenes and styrenes to prepare stilbene and stilbene derivatives. The reaction is successful with several functional groups on both the arene and the olefin including fluoride, chloride, trifluoromethyl, ester, nitro, acetate, cyanide, and ether groups. Reactions of monosubstituted arenes are selective for alkenylation at the meta and para positions, generally with approximately 2:1 selectivity, respectively. Resveratrol and (E)-1,2,3-trimethoxy-5-(4-methoxystyryl)benzene (DMU-212) are synthesized by this single-step approach in high yield. Comparison with palladium catalysis showed that rhodium catalysis is more selective for meta-functionalization for monosubstituted arenes and that the Rh catalysis has better tolerance of halogen groups.
- Jia, Xiaofan,Frye, Lucas I.,Zhu, Weihao,Gu, Shunyan,Gunnoe, T. Brent
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supporting information
p. 10534 - 10543
(2020/06/08)
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- Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
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The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the Zaitzev products is observed when the reaction is carried out in dichloroethane at reflux.
- Ganiu, Moshood O.,Cleveland, Alexander H.,Paul, Jarrod L.,Kartika, Rendy
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supporting information
p. 5611 - 5615
(2019/08/01)
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- Dipalladium(I) complexes of ortho- and para-functionalized 1,3-bis(aryl)triazenide ligands: Synthesis, structure and catalytic activity
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The synthesis and characterization of a series dipalladium(I) complexes of formulae [Pd{1-[2′-(methoxycarbonyl)phenyl]-3-[4′-X-phenyl]triazenide}]2 [X = F (4), Cl (5), Br (6)] are reported. The crystal structure of complex 4 was determined by X-ray diffraction studies. The previously reported dipalladium(I) 1–3 as well as the new complexes 4–6 were used as catalysts in the Heck and Suzuki couplings of different p-substituted bromobenzenes.
- Correa-Ayala, Erick,Campos-Alvarado, Carlos,Chávez, Daniel,Hernández-Ortega, Simón,Morales-Morales, David,Miranda-Soto, Valentín,Parra-Hake, Miguel
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supporting information
p. 130 - 138
(2019/03/12)
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- Palladium-catalyzed Mizoroki-Heck reactions in water using thermoresponsive polymer micelles
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Palladium-catalyzed Mizoroki-Heck reactions were carried out in water using thermoresponsive polymer micelles. The micelles were generated from thermoresponsive block copolymers consisting of a poly(N-isopropylacrylamide) (PNIPAAm) segment and a hydrophilic segment such as nonionic poly(ethylene glycol) (PEG) (2) and anionic poly(sodium p-styrenesulfonate) (PSSNa) (9). These copolymers exhibited lower critical solution temperature (LCST) behavior at ca. 40–50 °C and showed thermal stimuli-induced formation and dissociation of micelles. The copolymers formed micelles in aqueous solution at higher temperature, where catalytic reactions proceeded. At lower temperature, the micelles dissociated to form a clear solution, enabling efficient extraction of the products from aqueous reaction mixture. In the presence of these copolymers, palladium complexes catalyzed the coupling reactions between aryl iodides and alkene compounds inside the hydrophobic micelle cores in water under relatively milder conditions. Extraction of the products from the aqueous solution of 2 or 9 was found to be efficient enough in comparison with conventional surfactants.
- Suzuki, Noriyuki,Takabe, Taiga,Yamauchi, Yoshiko,Koyama, Shun,Koike, Rina,Rikukawa, Masahiro,Liao, Wei-Ting,Peng, Wen-Sheng,Tsai, Fu-Yu
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p. 1351 - 1358
(2019/02/06)
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- Synthesis of α-methylstilbenes using an aqueous Wittig methodology and application toward the development of potent human aromatase inhibitors
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The development of aqueous Wittig methodology for the synthesis of α-methylstilbenes using tripropylphosphine-derived phosphonium salts is described. The Wittig olefination reaction was high yielding and allowed isolation of stilbenes by simple filtration and washing with water. The novel phosphonium salts employed were accessed via a highly efficient, regioselective addition of hydrogen bromide to styrenes. Application of the α-methylstilbenes toward the synthesis of a collection of stilbenoid-triazoles is reported and their inhibition of CYP450 19A1 (aromatase) investigated. The overall structure-activity profile provided additional evidence on the aryl halide-ketone bioisostere hypothesis and identified 6c as a potent inhibitor of aromatase in vitro (Ki = 8 nM).
- Nielsen, Alexander J.,Raez-Villanueva, Sergio,Crankshaw, Denis J.,Holloway, Alison C.,McNulty, James
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p. 1395 - 1398
(2019/04/03)
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- Conversion of Carbonyl Compounds to Olefins via Enolate Intermediate
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A general and efficient protocol to synthesize substituted olefins from carbonyl compounds via nickel catalyzed C—O activation of enolates was developed. Besides ketones, aldehydes were also suitable substrates for the presented catalytic system to produce di- or tri- substituted olefins. It is worth noting that this approach exhibited good tolerance to highly reactive tertiary alcohols, which could not survive in other reported routes for converting carbonyl compounds to olefins. This method also showed good regio- and stereo-selectivity for olefin products. Preliminary mechanistic studies indicated that the reaction was accomplished through nickel catalyzed C—O activation of enolates, thus offering helpful contribution to current enol chemistry.
- Cao, Zhi-Chao,Xu, Pei-Lin,Luo, Qin-Yu,Li, Xiao-Lei,Yu, Da-Gang,Fang, Huayi,Shi, Zhang-Jie
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supporting information
p. 781 - 785
(2019/06/24)
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- Acceptorless dehydrogenative construction of CN and CC bonds through catalytic aza-Wittig and Wittig reactions in the presence of an air-stable ruthenium pincer complex
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The construction of CN bonds was achieved by the dehydrogenative coupling of alcohol and azide via aza-Wittig type reaction. The reaction is catalyzed by an acridine-derived ruthenium pincer complex and does not use any oxidant. The present protocol offers a wide substrate scope, including aliphatic, aryl or heteroaryl alcohol/azides. This expeditious protocol was successfully applied to construct a CC bond directly from alcohol via dehydrogenative Wittig reaction. Furthermore, the synthesis of structurally important pyrrolo[1,4]benzodiazepine derivatives was also achieved by this methodology.
- Biswas, Nandita,Das, Kalicharan,Sardar, Bitan,Srimani, DIpankar
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p. 6501 - 6512
(2019/05/24)
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- Nickel-Catalyzed Arylboration of Alkenylarenes: Synthesis of Boron-Substituted Quaternary Carbons and Regiodivergent Reactions
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A method for the construction of boron-substituted quaternary carbons or diarylquaternary carbons by arylboration of highly substituted alkenylarenes is presented. A wide range of alkenes and arylbromides can participate in this reaction thus allowing for a diverse assortment of products to be prepared. In addition, a solvent dependent regiodivergent arylboration of 1,2-disubstituted alkenylarenes is presented, thus greatly increasing the scope of products that can be accessed.
- Chen, Liang-An,Lear, Alan R.,Gao, Pin,Brown, M. Kevin
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supporting information
p. 10956 - 10960
(2019/07/08)
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- Synthesis of Polyethylene with In-Chain α,β-Unsaturated Ketone and Isolated Ketone Units: Pd-Catalyzed Ring-Opening Copolymerization of Cyclopropenone with Ethylene
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Although various functionalized units can be incorporated into polyolefins by transition metal catalyzed coordination copolymerizations of nonfunctionalized olefins with polar functional monomers, the incorporated functional units are largely limited to a C1 unit from either CO or C2 units from vinyl monomers. Reported here is the Pd-catalyzed copolymerization of ethylene with cyclopropenone, leading to incorporation of C3 units with functional groups, α,β-unsaturated ketones, in the chain. Coordination-insertion of the carbonyl group and ring opening of the strained three-membered ring are proposed as the key steps in the mechanism. Under different reaction conditions an isolated ketone structure was afforded as the major carbonyl unit, and could be generated by the copolymerization of ethylene with CO formed in situ from cyclopropenone.
- Wang, Xiaoming,Seidel, Falk William,Nozaki, Kyoko
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supporting information
p. 12955 - 12959
(2019/08/21)
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- Employing Water as the Hydride Source in Synthesis: A Case Study of Diboron Mediated Alkyne Hydroarylation
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We present an approach to utilize water as the hydride source via Pd(II)/Pd(0) catalysis. As a case study, we have achieved a diboron mediated Pd(II)-catalyzed hydroarylation of alkynes using arylboronic acids. This approach not only complements conventional reactivity of Pd via Pd(0)/Pd(II) cycle for the hydroarylation but also utilizes water as the hydride source. We believe this would particularly be beneficial in utilizing water as a reagent.
- Rao, Santhosh,Joy, M. Nibin,Prabhu, Kandikere Ramaiah
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p. 13707 - 13715
(2018/11/30)
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- Oxidative cross-coupling of allyl(trimethyl)silanes with aryl boronic acids by palladium catalysis
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The first oxidative cross-coupling of allylsilanes with aryl boronic acids has been developed by palladium catalysis. The reaction between β-substituted allyl(trimethyl)silanes and a wide range of aryl boronic acids afforded allylarenes in moderate to good yields and excellent selectivity. On the basis of experimental results and literature reports, it was suggested that the reaction might start from transmetalation of aryl boronic acid with AgOAc followed by transmetalation with Pd(II) to give an arylpalladium acetate complex as a key intermediate. This intermediate underwent either electrophilic addition/desilylation or transmetalation with allylsilane and subsequent reductive elimination to give the final product.
- Zhou, Zhibing,Hou, Zhen-Lin,Yang, Fan,Yao, Bo
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p. 7228 - 7236
(2018/11/03)
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- Olefination with Sulfonyl Halides and Esters: E-Selective Synthesis of Alkenes from Semistabilized Carbanion Precursors
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Carbanions of sulfonyl halides and activated sulfonates add to carbonyl compounds, and so-formed aldol-type adducts spontaneously fragment into olefins. This transformation mimics the one-pot Julia olefination with (hetero)aryl sulfones, but the mechanism of fragmentation involves a four-membered intermediate, typical for reactivity of phosphorus reagents. Moreover, in contrast to the reactions of sulfones, sulfonates of fluorinated alcohols (TFE and HFI) produce byproducts that are easily removed during workup. In our report, we focus on reactions of unstabilized and semistabilized carbanion precursors: alkylsulfonates, and allyl- and benzylsulfonates, respectively. In particular for semistabilized systems, olefins were synthesized as predominant E isomers in good yields. The presented studies reveal that optimal reaction conditions, including the type of base and alcohol groups of the sulfonates, are different depending on stabilization of the carbanion precursors and structure of the carbonyl substrates. The practical synthetic guide is supplemented with a discussion of the mechanism, based on reactivity studies of intermediates and identification of side-products.
- Górski, Bartosz,Basiak, Dariusz,Talko, Alicja,Basak, Tymoteusz,Mazurek, Tomasz,Barbasiewicz, Micha?
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supporting information
p. 1774 - 1784
(2018/04/27)
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- Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
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Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
- Jereb, Marjan,Vra?i?, Dejan
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p. 747 - 762
(2018/01/17)
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- Radical Cation Cyclopropanations via Chromium Photooxidative Catalysis
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The chromium photocatalyzed cyclopropanation of diazo reagents with electron-rich alkenes is described. The transformation occurs under mild conditions and features specific distinctions from traditional diazo-based cyclopropanations (e.g., avoiding β-hydride elimination, chemoselectivity considerations, etc.). The reaction appears to work most effectively using chromium catalysis, and a number of decorated cyclopropanes can be accessed in generally good yields.
- Sarabia, Francisco J.,Ferreira, Eric M.
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supporting information
p. 2865 - 2868
(2017/06/07)
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- Influence of the methyl group at C=C bridging bond of stilbene on the longest wavelength maximum in ultraviolet absorption spectra
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The compounds stilbenes XArCH=CHArY(XSBY) and 1,2-diphenylpropylenes XArC(Me)=CHArY(XSMBY) have bridging groups CH=CH and C(CH3)=CH, respectively, in which the C(CH3)=CH has a side-group CH3 at the carbon-carbon double bond. A series of XSMBY were synthesized, and their longest wavelength maximum λmax (nm) in ultraviolet absorption spectra were measured in this work. We investigated the change regularity of the νmax (cm-1, νmax?=?1/λmax) of XSMBY and compared it with that of XSBY. The results indicate that (1) there is no good linear relationship between the νmax of XSMBY and that of XSBY. (2) Because of the influence of the side-group CH3, in case of the same couple of groups X and Y, the λmax of XSMBY is shorter than that of XSBY, that is, it has a blue shift. (3) The cross-interaction between the side-group CH3 and Y has an important effect on the νmax of XSMBY, while the cross-interaction between the side-group CH3 and X has a little effect on the νmax and can be ignored. (4) The specific cross-interaction between X and Y has important effect on the νmax of XSMBY, whereas it has no important effect on the νmax of XSBY.
- Zhang, Yanxiu,Cao, Chao-Tun,Zhang, Jingyuan,Cao, Chenzhong
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- The effect of framework functionality on the catalytic activation of supported Pd nanoparticles in the Mizoroki–Heck coupling reaction
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Palladium nanoparticles (Pd-NPs) were supported on functional and nonfunctional Co-coordination polymers (Pd/CoBDCNH2 and Pd/CoBDC). Advanced analytical techniques revealed that Pd-NPs are supported on the external surface of the polymer framework and the functionalized framework possesses effective influence to prevent Pd-NP aggregation. Supported Pd-NPs were effectively applied as heterogeneous recyclable catalysts in the Mizoroki–Heck C–C cross coupling reactions of iodobenzene and either aromatic or aliphatic terminal alkenes. Catalytic results exhibited that highly dispersed Pd-NPs with low loading (1%) on the functional polymer (Pd/CoBDCNH2) are more effective than aggregated Pd-NPs with high loading (9%) on the nonfunctional polymer (Pd/CoBDC). Both catalysts can simultaneously provide high activity and selectivity to E-coupled products, high efficiency in low amounts, easy separation of heterogeneous catalyst and appropriate performance in the recycling reaction without addition of a reducing agent.
- Ashouri, Fatemeh,Zare, Maryam,Bagherzadeh, Mojtaba
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p. 107 - 115
(2017/01/22)
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- Palladium/copper-catalyzed arylation of alkenes with N′-acyl arylhydrazines
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A novel ligand-free palladium/copper-catalyzed Heck-type coupling reaction of alkenes and N′-acyl arylhydrazines has been developed by using air as the terminal oxidant. This protocol features wide functional group tolerance and produces highly chemoselective and regioselective products with good to excellent yields.
- Zhang, Ji-Quan,Cao, Jun,Li, Wei,Li, Shu-Min,Li, Yong-Kang,Wang, Jian-Ta,Tang, Lei
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supporting information
p. 437 - 441
(2017/02/05)
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- A New Mode of Operation of Pd-NHC Systems Studied in a Catalytic Mizoroki-Heck Reaction
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Metal complexes bearing N-heterocyclic carbene (NHC) ligands are typically considered the system of choice for homogeneous catalysis with well-defined molecular active species due to their stable metal-ligand framework. A detailed study involving 19 different Pd-NHC complexes with imidazolium, benzimidazolium, and triazolium ligands has been carried out in the present work and revealed a new mode of operation of metal-NHC systems. The catalytic activity of the studied Pd-NHC systems is predominantly determined by the cleavage of the metal-NHC bond, while the catalyst performance is strongly affected by the stabilization of in situ formed metal clusters. In the present study, the formation of Pd nanoparticles was observed from a broad range of metal complexes with NHC ligands under standard Mizoroki-Heck reaction conditions. A mechanistic analysis revealed two different pathways to connect Pd-NHC complexes to "cocktail"-type catalysis: (i) reductive elimination from a Pd(II) intermediate and the release of NHC-containing byproducts and (ii) dissociation of NHC ligands from Pd intermediates. Metal-NHC systems are ubiquitously applied in modern organic synthesis and catalysis, while the new mode of operation revealed in the present study guides catalyst design and opens a variety of novel opportunities. As shown by experimental studies and theoretical calculations, metal clusters and nanoparticles can be readily formed from M-NHC complexes after formation of new M-C or M-H bonds followed by C-NHC or H-NHC coupling. Thus, a combination of a classical molecular mode of operation and a novel cocktail-type mode of operation, described in the present study, may be anticipated as an intrinsic feature of M-NHC catalytic systems.
- Astakhov, Alexander V.,Khazipov, Oleg V.,Chernenko, Andrey Yu.,Pasyukov, Dmitry V.,Kashin, Alexey S.,Gordeev, Evgeniy G.,Khrustalev, Victor N.,Chernyshev, Victor M.,Ananikov, Valentine P.
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supporting information
p. 1981 - 1992
(2017/06/14)
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- Highly-phosphorescent tungsten(0) carbonyl pyridyl-imidazole complexes as photosensitisers
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Photoluminescence data are reported for two W(CO)4L complexes (L = 2-(1H-imidazol-2-yl)pyridine and 2-(2′-pyridyl)benzimidazole) in room-temperature solutions. The bidentate ligands consist of a pyridine and an imidazole moiety connected by a C-C bond. The complexes have been found to exhibit enhanced phosphorescence from the metal-to-ligand charge transfer (MLCT) excited state with quantum yields in the order of 10-3, almost two orders of magnitude higher than those reported for W(CO)4(diimine) complexes. One of the complexes W(CO)4(2-(2′-pyridyl)benzimidazole) can serve as an efficient visible-light photosensitiser for the isomerisation of aromatic alkenes with efficiency comparable to and even exceeding that of the well-studied ruthenium tris-bipyridine complex, Ru(bpy)Cl2.
- Lee, Jia Jin,Yap, Chew Pheng,Chwee, Tsz Sian,Fan, Wai Yip
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p. 11008 - 11012
(2017/08/30)
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- Doubly Regioselective C-H Hydroarylation of Unsymmetrical Alkynes Using Carboxylates as Deciduous Directing Groups
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A catalyst system composed of [(C6Me6)RuCl2]2, potassium carbonate/guanidine carbonate, and mesitoic acid efficiently promotes the doubly regioselective C-H hydroarylation of unsymmetrical alkynes. The process involves carboxylate-directed ortho-C-H bond activation followed by regioselective addition to the alkyne C-C triple bond with concerted decarboxylation. This action of the carboxylate as a deciduous directing group ensures exclusive monovinylation with high selectivity for the (E)-1,2-diarylalkene.
- Biafora, Agostino,Khan, Bilal A.,Bahri, Janet,Hewer, Joachim M.,Goossen, Lukas J.
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supporting information
p. 1232 - 1235
(2017/03/14)
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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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- Ruthenium(II)-catalyzed olefination: Via carbonyl reductive cross-coupling
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Natural availability of carbonyl groups offers reductive carbonyl coupling tremendous synthetic potential for efficient olefin synthesis, yet the catalytic carbonyl cross-coupling remains largely elusive. We report herein such a reaction, mediated by hydrazine under ruthenium(ii) catalysis. This method enables facile and selective cross-couplings of two unsymmetrical carbonyl compounds in either an intermolecular or intramolecular fashion. Moreover, this chemistry accommodates a variety of substrates, proceeds under mild reaction conditions with good functional group tolerance, and generates stoichiometric benign byproducts. Importantly, the coexistence of KOtBu and bidentate phosphine dmpe is vital to this transformation.
- Wei, Wei,Dai, Xi-Jie,Wang, Haining,Li, Chenchen,Yang, Xiaobo,Li, Chao-Jun
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p. 8193 - 8197
(2017/11/27)
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- Thermally Induced Carbohydroxylation of Styrenes with Aryldiazonium Salts
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The radical carbohydroxylation of styrenes with aryldiazonium salts has been achieved under mild thermal conditions. A broad range of aryldiazonium salts was tolerated, and the reaction principle based on a radical–polar crossover mechanism could be exten
- Kindt, Stephanie,Wicht, Karina,Heinrich, Markus R.
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p. 8744 - 8747
(2016/07/21)
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- Chloride-Bridged Dinuclear Rhodium(III) Complexes Bearing Chiral Diphosphine Ligands: Catalyst Precursors for Asymmetric Hydrogenation of Simple Olefins
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Efficient rhodium(III) catalysts were developed for asymmetric hydrogenation of simple olefins. A new series of chloride-bridged dinuclear rhodium(III) complexes 1 were synthesized from the rhodium(I) precursor [RhCl(cod)]2, chiral diphosphine ligands, and hydrochloric acid. Complexes from the series acted as efficient catalysts for asymmetric hydrogenation of (E)-prop-1-ene-1,2-diyldibenzene and its derivatives without any directing groups, in sharp contrast to widely used rhodium(I) catalytic systems that require a directing group for high enantioselectivity. The catalytic system was applied to asymmetric hydrogenation of allylic alcohols, alkenylboranes, and unsaturated cyclic sulfones. Control experiments support the superiority of dinuclear rhodium(III) complexes 1 over typical rhodium(I) catalytic systems.
- Kita, Yusuke,Hida, Shoji,Higashihara, Kenya,Jena, Himanshu Sekhar,Higashida, Kosuke,Mashima, Kazushi
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supporting information
p. 8299 - 8303
(2016/07/19)
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- A simple, phosphine free, reusable Pd(ii)-2,2′-dihydroxybenzophenone-SBA-15 catalyst for arylation and hydrogenation reactions of alkenes
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An efficient, simple, phosphine and co-catalyst free C-C coupling reaction heterogeneous catalyst via a post grafting method is developed and reported. A covalently anchored phosphine free Pd(ii) based 2,2′-dihydroxybenzophenone (DHBP) complex over organofunctionalized SBA-15 has been synthesized by the reaction between aminofunctionalized SBA-15 (NH2SBA-15) and a 2,2′-dihydroxybenzophenone (DHBP) ligand, and further complexation with Pd(ii)Cl2 to get Pd(ii)-DHBP@SBA-15. The synthesized catalysts were characterized by elemental analysis, XRD, N2 sorption analyses, TG, DTA, FT-IR, solid state 13C and 29Si NMR spectra, XPS, UV-Visible, SEM, EDAX and TEM. The synthesized catalysts were screened in arylation (Heck reactions) and hydrogenation reactions of alkenes, and the results show that Pd(ii)-DHBP@SBA-15 exhibits high conversion and selectivity towards arylation and hydrogenation reactions of alkenes with high stability. The anchored solid catalysts can be recycled effectively and reused several times without major loss in activity.
- Lazar, Anish,Vinod, Chathakudath P.,Singh, Anand Pal
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p. 2423 - 2432
(2016/03/19)
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- Allylic C–H Activation of Olefins by a TpMe2IrIII Compound
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The IrIIIcompound [TpMe2Ir(C6H5)2(N2)] (1) [TpMe2= hydridotris(3,5-dimethylpyrazolyl)borate] reacts with 1-hexene, propene, α-methylstyrene, and 2,3-dimethylbutadiene to yield organometallic products that derive from allylic C–H activations (complexes 3 from 1-hexene, 2 from propene, 5 from α-methylstyrene, and 7, 8, and 9 from 2,3-dimethylbutadiene), in all cases along with organic products formed in catalytic (Ir-induced) dehydrogenative coupling of benzene (the solvent of the reaction) and the corresponding olefin, with the latter also acting as the hydrogen scavenger in each case. Differently, complex 1 reacts with (E)-β-methylstyrene and cyclohexadiene to yield complex 2 and the known (η4-cyclohexadiene)IrIderivative 6, respectively. Finally, compound 1 reacts under mild conditions with cyclopentadiene and methylcyclopentadiene with the generation of phenyl derivatives 11 and 12 in which the corresponding cyclopentadienyl ligand adopts the η5coordination and forces the TpMe2ligand to coordinate in the κ2mode.
- Cristóbal, Crispín,Santos, Laura L.,Gutiérrez-González, Rubén,álvarez, Eleuterio,Paneque, Margarita,Poveda, Manuel L.
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p. 2534 - 2542
(2016/07/06)
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- Hydrophenylation of internal alkynes with boronic acids catalysed by a Ni-Zn hydroxy double salt-intercalated anionic rhodium(III) complex
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[Rh(OH)6]3- intercalated Ni-Zn mixed basic salt (Rh/NiZn) acts as an efficient catalyst for the hydrophenylation of internal alkynes with arylboronic acids under mild conditions. The turnover number per Rh site approached 740 in the reaction between 4-octyne and phenylboronic acid. The catalytic monomeric Rh(iii) complex is stabilised within the NiZn interlayers, attributable to a strong electrostatic interaction, promoting its re-use.
- Hara, Takayoshi,Fujita, Nozomi,Ichikuni, Nobuyuki,Wilson, Karen,Lee, Adam F.,Shimazu, Shogo
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p. 863 - 868
(2016/02/18)
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- Nickel-catalyzed synthesis of (E)-olefins from benzylic alcohol derivatives and arylacetonitriles via C-O activation
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An efficient Ni-catalyzed synthesis of (E)-olefins using the readily available benzylic alcohol derivatives and arylacetonitriles is described. This transformation should proceed via a tandem process involving nickel-catalyzed cross coupling via C-O activation and subsequent stereoselective E2 elimination.
- Xiao, Jing,Yang, Jia,Chen, Tieqiao,Han, Li-Biao
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supporting information
p. 2157 - 2160
(2016/02/05)
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- Iron-Catalyzed e?Selective dehydrogenative borylation of vinylarenes with pinacolborane
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We report the dehydrogenative borylation of vinylarenes with pinacolborane (HBpin) catalyzed by an iron(0) complex “(PMe3)4Fe”. A variety of monosubstituted and disubstituted vinylarenes underwent this iron-catalyzed transformation, affording E-vinyl boronate esters (VBEs) selectively in hi h ields. In addition we coupled this iron-catal zed dehydrogenative borylation with further transformations of the resulting vinyl boronate esters and developed various one-pot procedures for the functionalization of the vinylic C?H bonds in vinylarenes. Mechanistic studies reveal that this Fe-catalyzed reaction proceeds through syn-insertion of vinylarenes into a Fe-boryl species followed by β-hydrogen elimination from a syn coplanar conformation of the borylalkyl iron intermediate.
- Wang, Chao,Wu, Caizhi,Ge, Shaozhong
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p. 7585 - 7589
(2018/05/23)
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- 1,1′-methylene-3,3′-bis[(N -(tert -butyl)imidazol-2-ylidene] and Its effect in palladium-catalyzed C-C coupling
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A catalytic system utilizing a chelate carbene ligand containing bulk tert-butyl groups is described for palladium-catalyzed Heck and Suzuki coupling reactions. The Heck reaction focused on the coupling of different aryl bromides with mono- and 1,1-disubstituted olefins while the Suzuki reaction involved the coupling of aryl bromides and phenylboronic acid to afford the corresponding biphenyls. The catalyst system performs well with low Pd(OAc)2 levels (0.025 mol% Pd). In all cases with monosubstituted olefins, the trans-configured products were obtained, while the results of Heck reaction of 1,1-disubstituted olefins exhibited a high selectivity favoring the terminal product.
- Nadri, Shirin,Rafiee, Ezzat,Jamali, Sirous,Joshaghani, Mohammad
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supporting information
p. 619 - 624
(2015/03/14)
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- Arylation of alkynes over hydrotalcite docked Rh-m-TPPTC complex
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Rh-m-TPPTC complex was successful immobilized onto a hydrotalcite Zn-Al to convert selectively in aqueous media both the symmetric and nonsymmetric alkynes into functionalized alkenes, with boronic acids. The complex preserved its activity after the ionic exchange, leading to excellent results (~87%) for the symmetric alkynes and also for the non-symmetrical alkynes (up to 99%).
- Nea?u, Florentina,Ciobanu, M?d?lina,?toflea, Laura E.,Frunz?, Ligia,Parvulescu, Vasile I.,Michelet, Véronique
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p. 155 - 162
(2015/03/30)
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- Microwave role in the thermally induced SRN1 reaction for α-arylation of ketones
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The coupling between iodobenzene and the enolate anion of acetophenone is accelerated by microwave irradiation. This increase in reaction rate is only ascribed to thermal effects. The coupling reaction gave the corresponding substitution product 1,2-di-phenylethanone in a 50% yield when microwave irradiation was applied between 15-60 s according to the intensity of the pulse. Moreover, this reaction is effective in a temperature window of 70-120 °C. The presence of ionic and dipolar species is not involved in the initiation process as molecular radiators. The excess of tBuOK in the reaction medium may also act as an electron donor helping to generate radicals when the solution temperature increases to 70 °C. This journal is
- Caminos, Daniel A.,Garro, Alexis D.,Soria-Castro, Silvia M.,Pe?é?ory, Alicia B.
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p. 20058 - 20065
(2015/03/30)
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- Carboncarbon bond forming reactions: Application of covalently anchored 2,4,6-triallyloxy-1,3,5-triazine (TAT) Pd(II) complex over modified surface of SBA-15 to Heck, Suzuki, Sonogashira and Hiyama cross coupling reactions
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A highly active SBA-15-TAT-Pd(II) catalyst was synthesized from organofunctionalized SBA-15 and 2,4,6-triallyloxy-1,3,5-triazine. The catalyst was employed in carrying out Heck, "copper-free" Sonogashira, Suzuki and Hiyama cross coupling reactions. Under the optimized conditions the catalyst displays excellent catalytic activity in delivering the desired products in good to excellent yields. The catalytic system exhibited superior activity regarding the time taken for the completion of reaction, isolation, Pd loading (0.62 mmol%) and yields of products as compared to the earlier reported heterogeneous SBA-15 anchored Pd catalysts. The catalyst could be recycled and reused for five times without any appreciable loss of catalytic activity.
- Singh, Chandani,Jawade, Kiran,Sharma, Priti,Singh, Anand P.,Kumar, Pradeep
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- General Olefin Synthesis by the Palladium-Catalyzed Heck Reaction of Amides: Sterically Controlled Chemoselective N-C Activation
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Metal-catalyzed reactions of amides proceeding via metal insertion into the N-CO bond are severely underdeveloped due to resonance stabilization of the amide bond. Herein we report the first Heck reaction of amides proceeding via highly chemoselective N-CO cleavage catalyzed by Pd0 utilizing amide bond ground-state destabilization. Conceptually, this transformation provides access to a myriad of metal-catalyzed transformations of amides via metal insertion/decarbonylation.
- Meng, Guangrong,Szostak, Michal
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supporting information
p. 14518 - 14522
(2016/01/25)
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