- Rhodium-Catalyzed Annulation of Phenacyl Ammonium Salts with Propargylic Alcohols via a Sequential Dual C-H and a C-C Bond Activation: Modular Entry to Diverse Isochromenones
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Given their omnipresence in natural products and pharmaceuticals, isochromenone congeners are one of the most privileged scaffolds to synthetic chemists. Disclosed herein is a dual (ortho/meta) C-H and C-C activation of phenacyl ammonium salts (acylammonium as traceless directing group) toward annulation with propargylic alcohols to accomplish rapid access for novel isochromenones by means of rhodium catalysis from readily available starting materials. This operationally simple protocol features broad substrate scope and wide functional group tolerance. Importantly, the protocol circumvents the need of any stoichiometric metal oxidants and proceeds under aerobic conditions.
- Nanubolu, Jagadeesh Babu,Reddy Singam, Maneesh Kumar,Sridhar Reddy, Maddi,Suresh, Vavilapalli,Suri Babu, Undamatla
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supporting information
p. 7888 - 7893
(2021/10/25)
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- Bimetal Cooperatively Catalyzed Arylalkynylation of Alkynylsilanes
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An unprecedented Pd/Rh cooperatively catalyzed arylalkynylation of alkynylsilanes was developed to merge an alkynylidene moiety with benzosilacycle. These silaarenes possess a particular aggregation-induced emission behavior. Mechanistic investigations demonstrate that the relay trimetallic transmetalation plays a pivotal role in governing this transformation.
- Chen, Xing,Li, Mengke,Liu, Zhipeng,Yang, Can,Xie, Haisheng,Hu, Xinwei,Su, Shi-Jian,Jiang, Huanfeng,Zeng, Wei
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supporting information
p. 6724 - 6728
(2021/09/08)
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- Dual Palladium/Copper-Catalyzed anti-Selective Intermolecular Allenylsilylation of Terminal Alkynes: Entry to (E)-Silyl Enallenes
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A palladium-/copper-cocatalyzed three-component trans-allenylsilylation of terminal alkynes with propargyl acetates and PhMe2SiBpin is described, which is driven by the regioselective allenylation of the alkyne with propargyl acetates and then silylation. This method allows the simultaneous incorporation of an allene and silicon across the CC bond and provides a highly chemo-, regio-, and stereoselective alkyne difunctionalization route to the synthesis of valuable (E)-silyl enallenes. The utility of this method is highlighted by late-stage derivatization of bioactive compounds.
- Yang, Liang-Feng,Wang, Qiu-An,Li, Jin-Heng
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supporting information
p. 6553 - 6557
(2021/09/02)
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- Rhodium-catalyzed oxidative coupling of benzoic acids with propargyl alcohols: An efficient access to isocoumarins
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An efficient protocol of Rh(III)-catalyzed oxidative cyclization of benzoic acids with propargyl alcohols to give substituted isocoumarins under mild conditions was reported. A variety of substrates were applied in this reaction in yields up to 89%.
- Luo, Feihua,He, Shuhua,Gou, Quan,Chen, Jinyang,Zhang, mingzhong
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supporting information
(2020/12/29)
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- Design, synthesis, antileishmanial, and antifungal biological evaluation of novel 3,5-disubstituted isoxazole compounds based on 5-nitrofuran scaffolds
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Nineteen 3,5-disubstituted-isoxazole analogs were synthesized based on nitrofuran scaffolds, by a [3 + 2] cycloaddition reaction between terminal acetylenes and 5-nitrofuran chloro-oxime. The compounds were obtained in moderate to very good yields (45–91%). The antileishmanial activity was assayed against the promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. Alkylchlorinated compounds 14p–r were active on both the promastigote and amastigote forms, with emphasis on compound 14p, which showed strong activity against the amastigote form (IC50 = 0.6 μM and selectivity index [SI] = 5.2). In the alkyl series, compound 14o stands out with an IC50 = 8.5 μM and SI = 8.0 on the amastigote form. In the aromatic series, the most active compounds were those containing electron-donor groups, such as trimethoxy isoxazole 14g (IC50 = 1.2 μM and SI = 20.2); compound 14h, with IC50 = 7.0 μM and SI = 6.1; and compound 14j containing the 4-SCH3 group, with IC50 = 5.7 μM and SI = 10.2. In addition, the antifungal activity of 19 nitrofuran isoxazoles was evaluated against five strains of Candida (C. albicans, C. parapsilosis, C. krusei, C. tropicalis, and C. glabrata). Eleven isoxazole derivatives were active against C. parapsilosis, and compound 14o was found to be the most active (minimal inhibitory concentration [MIC] = 3.4 μM) for this strain. Compound 14p was active against all the strains tested, with an MIC = 17.5 μM for C. glabrata, lower than that of the fluconazole used as the reference drug.
- Trefzger, Ozildéia S.,Barbosa, Natália V.,Scapolatempo, Renata L.,das Neves, Amarith R.,Ortale, Maria L. F. S.,Carvalho, Diego B.,Honorato, Ant?nio M.,Fragoso, Mariana R.,Shuiguemoto, Cristiane Y. K.,Perdomo, Renata T.,Matos, Maria F. C.,Chang, Marilene R.,Arruda, Carla C. P.,Baroni, Adriano C. M.
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- One-pot synthesis of unsymmetrical 1,3-butadiyne derivatives and their application in the synthesis of unsymmetrical 2,5-diarylthiophenes
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A one-pot protocol was developed for the synthesis of unsymmetrical 1,3-butadiynes. The procedure is based on two sequential reactions: deprotection of R–C≡C–C≡C– C(Me)2OH derivatives in a retro-Favorskii reaction to furnish a terminal 1,3-butadiyne compound, which reacted with aryl iod-ides in a Sonogashira-type cross-coupling reaction catalyzed by Pd(PPh3)4 and CuI, using TBAOH as activator and toluene as solvent under reflux for 10 min. We also studied in situ thiocycli-zation of 1,3-butadiynes, leading to unsymmetrical 2,5-diaryl-thiophenes. The principal features of this method are operational simplicity, good substrate scope, very fast reaction, and high yields.
- Andrade, Camila B.,Carvalho, Diego B.,Trefzger, Ozildéia S.,Kassab, Najla M.,Guerrero, Palimécio G.,Barbosa, Sandro L.,Shiguemoto, Cristiane Y. K.,Baroni, Adriano C. M.
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supporting information
p. 696 - 704
(2019/01/04)
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- Palladium(II)/Lewis acid cocatalyzed oxidative annulation of 2-alkenylanilines and propargylic esters: An access to benzo[ b]azepines
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An attractive approach to valuable yet synthetically challenging benzo[b]azepines was established via palladium(II)/Lewis acid cocatalyzed oxidative [5 + 2] annulation of readily available 2-alkenylanilines and propargylic esters. The protocol features mild reaction conditions and good functional group tolerance, constituting an array of benzo[b]azepines in yields of 30-75%.
- Qiao, Hong,Zhang, Shengjun,Li, Kangkang,Cao, Zhengqiang,Zeng, Fanlong
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p. 10843 - 10851
(2019/09/12)
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- Design, synthesis and antitrypanosomatid activities of 3,5-diaryl-isoxazole analogues based on neolignans veraguensin, grandisin and machilin G
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Using bioisosterism as a medicinal chemistry tool, 16 3,5-diaryl-isoxazole analogues of the tetrahydrofuran neolignans veraguensin, grandisin and machilin G were synthesized via 1,3-dipolar cycloaddition reactions, with yields from 43% to 90%. Antitrypanosomatid activities were evaluated against Trypanosoma cruzi, Leishmania (L.) amazonensis and Leishmania (V.) braziliensis. All compounds were selective for the Leishmania genus and inactive against T.?cruzi. Isoxazole analogues showed a standard activity on both promastigotes of L.?amazonensis and L.?braziliensis. The most active compounds were 15, 16 and 19 with IC50 values of 2.0, 3.3 and 9.5?μM against L.?amazonensis and IC50 values of 1.2, 2.1 and 6.4?μM on L.?braziliensis, respectively. All compounds were noncytotoxic, showing lower cytotoxicity (>250?μM) than pentamidine (78.9?μM). Regarding the structure–activity relationship (SAR), the methylenedioxy group was essential to antileishmanial activity against promastigotes. Replacement of the tetrahydrofuran nucleus by an isoxazole core improved the antileishmanial activity.
- Trefzger, Ozildéia S.,das Neves, Amarith R.,Barbosa, Natália V.,Carvalho, Diego B.,Pereira, Indiara C.,Perdomo, Renata T.,Matos, Maria F. C.,Yoshida, Nidia C.,Kato, Massuo J.,de Albuquerque, Sérgio,Arruda, Carla C. P.,Baroni, Adriano C. M.
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p. 313 - 324
(2018/11/30)
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- Catalyst-Controlled [3 + 2] and [4 + 2] Annulations of Oximes with Propargyl Alcohols: Divergent Access to Indenamines and Isoquinolines
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Rhodium(III)- and iridium(III)-catalyzed C-H activation of oximes and coupling with propargyl alcohols is discussed. Depending on the catalyst, the reaction pathway switched between [3 + 2] and [4 + 2] annulations, thus giving divergent access to indenami
- Gong, Wanchun,Zhou, Zhi,Shi, Jingjing,Wu, Bo,Huang, Biyun,Yi, Wei
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supporting information
p. 182 - 185
(2018/01/17)
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- DBU-promoted carbonylative synthesis of 1,3-oxathiolan-2-ones from propargylic alcohols with TFBen as the CO source
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A DBU-promoted carbonylative cyclization of propargylic alcohols with sulfur was developed. Various 1,3-oxathiolan-2-ones were produced in 61-98% yields under mild conditions in the absence of metal catalysts. TFBen (benzene-1,3,5-triyl triformate) as an efficient and solid CO surrogate and S8 as an ideal sulfur source were employed and incorporated.
- Ying, Jun,Zhou, Chao,Wu, Xiao-Feng
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supporting information
p. 1065 - 1067
(2018/02/22)
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- α-Hydroxy Ketones as Masked Ester Donors in Br?nsted Base Catalyzed Conjugate Additions to Nitroalkenes
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The catalyst-controlled enantioselective direct addition reaction of enolizable esters and related carboxylic acid derivatives to π electrophiles remains a difficult synthetic transformation. In this study, the suitability of α-hydroxy ketones as ester equivalents capable of being activated by bifunctional Br?nsted base catalysts in the context of conjugate addition reactions to nitroolefins is demonstrated. The scope of the reaction, which affords the corresponding Michael adducts with very high stereoselectivity (diastereomeric ratio (d.r.) ≥95:5, up to 99 % enantiomeric excess (ee)), and its limitations are explored, as is the aftermath elaboration of adducts into densely functionalized enantioenriched products.
- Olaizola, Iurre,Campano, Teresa E.,Iriarte, Igor,Vera, Silvia,Mielgo, Antonia,García, Jesús M.,Odriozola, José M.,Oiarbide, Mikel,Palomo, Claudio
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supporting information
p. 3893 - 3901
(2018/03/21)
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- Cleavage of C–C and C–O Bonds to Form C–C Bonds: Direct Cross-Coupling between Acetylenic Alcohols and Benzylic Carbonates
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A palladium-catalyzed cross-coupling reaction between C(sp) and C(sp3) centers was achieved in excellent yields via C–C bond cleavage and C–O bond cleavage. This procedure uses relatively stable acetylenic alcohols as reactants instead of unsta
- Mi, Zhiyuan,Tang, Jiahao,Guan, Zhipeng,Shi, Wei,Chen, Hao
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supporting information
p. 4479 - 4482
(2018/09/10)
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- Tert-butoxy rare earth/sodium impurity bimetallic complex, as well as preparation method and use thereof
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The invention discloses a tert-butoxy rare earth/sodium hetero-bimetallic complex as well as a preparation method and use thereof. The molecular formula of the tert-butoxy rare earth/sodium hetero-bimetallic complex is LnNa8[OC(CH3)3]10(OH), and Ln repres
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Paragraph 0071-0072
(2017/07/13)
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- Alkyne Activation by a Porous Silver Coordination Polymer for Heterogeneous Catalysis of Carbon Dioxide Cycloaddition
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The widely studied porous coordination polymers, possessing large pores to adsorb waste carbon dioxide gas and further transform it into valuable chemical products, have been attracting research interest, both industrially and academically. The active silver(I) ions endow the specific alkynophilicity to activate C≡C bonds of alkyne-containing molecules via π activation. Incorporating catalytic Ag metal sites into the porous frameworks represents a promising approach to construct heterogeneous catalysts that cyclize propargylic alcohols with CO2, which is highly desirable for the environmentally benign conversion of carbon dioxide to fine chemicals. We report the preparation of porous coordination polymers (PCPs) with active silver sites and efficient silver-silver bond formation by carefully modifying the coordination geometries of the silver sites. The decentralized silver(I) chains in the porous frameworks enable the efficient conversion of CO2 and derivatives of acetylene to α-alkylidene cyclic carbonates in a heterogeneous manner. X-ray structure analysis reveals two kinds of substrate molecules positioned within the pores of the framework, which correspond to trapping and activated modes through the multiple interactions with the functional Ag chains. The example of tandem conversion of simple alkynes and carbon dioxide to α-alkylidene cyclic carbonates is also presented. The well-positioned catalytic silver(I) sites and the crystalline properties of the frameworks facilitated the structural analyses of the intermediates of each catalytic step, providing knowledge of the synergistic nature of the σ and π activation of C≡C bonds. The successful catalysis of azide-alkyne cycloaddition and synthesis of propargylic alcohols via terminal alkynes could also give another indicator for the activation properties of Ag sites.
- Zhou, Zhen,He, Cheng,Yang, Lu,Wang, Yefei,Liu, Tao,Duan, Chunying
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p. 2248 - 2256
(2017/08/14)
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- Gold-Catalyzed [4+2]- and [3+3]-Annulations of Ynamides with 1-Yn-3-ols to Access Six-Membered Carbocycles and Oxacycles via Three Distinct Cyclizations
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Three distinct strategies for catalytic annulations between ynamides and 1-yn-3-ols are described; the resulting carbo- and heterocycles were produced efficiently in one-pot operations using a gold catalyst. The chemoselectivities of these annulations are controlled by variations of the substituents of the ynamides and the 1-yn-3-ols. This reaction sequence involves initial alkoxylations of ynamides, followed by Claisen rearrangement of propargylic enol ethers, and ends with 6-endo-trig cyclizations of 1-allenyl-5-amide intermediates. Among these cascade annulations, the cyclizations of 5-allenyl-1-amides to yield 5,6-dihydro-2-pyranones and 6-alkylenecyclohex-2-ene-1-carboxamides are unprecedented in the literature. (Figure presented.).
- Giri, Sovan Sundar,Liu, Rai-Shung
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supporting information
p. 3311 - 3318
(2017/09/13)
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- Asymmetric Intermolecular Heck Reaction of Propargylic Acetates and Cycloalkenes to Access Fused Cyclobutenes
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An asymmetric Heck annulation of propargylic acetates with several types of cyclic olefins affords highly strained cyclobutenes in high enantioselectivity.
- Jiao, Zhiwei,Shi, Qi,Zhou, Jianrong Steve
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supporting information
p. 14567 - 14571
(2017/10/23)
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- Synthesis and Simple Immobilization of Palladium(II) Acyclic Diaminocarbene Complexes on Polystyrene Support as Efficient Catalysts for Sonogashira and Suzuki-Miyaura Cross-Coupling
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Immobilization of palladium(II) acyclic diaminocarbene (Pd(II)-ADC) complexes on a resin support surface has been easily performed by metal-mediated addition of amino groups of benzhydrylamine-polystyrene to the coordinated isocyanide ligand of cis-PdCl2(CNR)2 (R = t-Bu, Cy). The investigation of the benzhydrylamine reaction with palladium-coordinated isocyanides in solution has revealed that, depending on the reaction conditions, two carbene-type complexes can be obtained as a result of the addition to the CN triple bond, as well as a third complex which is formed via substitution of the isocyanide ligand by benzhydrylamine. Nucleophilic addition of an amino group to the isocyanide ligand has led to a cis-acyclic diaminocarbene complex or a cationic diaminocarbene complex with trans configuration and an intramolecular hydrogen-bonded chloride anion (the nature of this noncovalent interaction was analyzed by DFT calculations, including AIM analysis). The unsupported and resin-supported palladium catalysts have demonstrated high catalytic activity in both Sonogashira and Suzuki-Miyaura cross-coupling. The supported catalyst can be recovered and repeatedly reused without a significant loss in efficiency. The degree of the palladium binding with polystyrene, the oxidation state, and the palladium leaching level were investigated by XPS and XRF analyses.
- Mikhaylov, Vladimir N.,Sorokoumov, Viktor N.,Korvinson, Kirill A.,Novikov, Alexander S.,Balova, Irina A.
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p. 1684 - 1697
(2016/07/06)
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- Palladium-Catalyzed Nitration of Meyer-Schuster Intermediates with tBuONO as Nitrogen Source at Ambient Temperature
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A novel domino palladium-catalyzed nitration of Meyer-Schuster intermediates which were generated in situ from propargylic alcohols was developed, by the use of t-BuONO, leading to α-nitro enones in good to excellent yields at room temperature with a broa
- Lin, Yuanguang,Kong, Weiguang,Song, Qiuling
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supporting information
p. 3702 - 3705
(2016/08/16)
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- Antileishmanial activity and structure-activity relationship of triazolic compounds derived from the neolignans grandisin, veraguensin, and machilin G
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Sixteen 1,4-diaryl-1,2,3-triazole compounds 4-19 derived from the tetrahydrofuran neolignans veraguensin 1, grandisin 2, and machilin G 3 were tested against Leishmania (Leishmania) amazonensis intracellular amastigotes. Triazole compounds 4-19 were synthetized via Click Chemistry strategy by 1,3-dipolar cycloaddition between terminal acetylenes and aryl azides containing methoxy and methylenedioxy groups as substituents. Our results suggest that most derivatives were active against intracellular amastigotes, with IC50 values ranging from 4.4 to 32.7 μM. The index of molecular hydrophobicity (ClogP) ranged from 2.8 to 3.4, reflecting a lipophilicity/hydrosolubility rate suitable for transport across membranes, which may have resulted in the potent antileishmanial activity observed. Regarding structure-activity relationship (SAR), compounds 14 and 19, containing a trimethoxy group, were the most active (IC50 values of 5.6 and 4.4 μM, respectively), with low cytotoxicity on mammalian cells (SI = 14.1 and 10.6). These compounds induced nitric oxide production by the host macrophage cells, which could be suggested as the mechanism involved in the intracellular killing of parasites. These results would be useful for the planning of new derivatives with higher antileishmanial activities.
- Costa, Eduarda C.,Cassamale, Tatiana B.,Carvalho, Diego B.,Bosquiroli, Lauriane S. S.,Ojeda, Mariáh,Ximenes, Thalita V.,Matos, Maria F. C.,Kadri, M?nica C. T.,Baroni, Adriano C. M.,Arruda, Carla C. P.
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- Synthesis and Antitrypanosomastid Activity of 1,4-Diaryl-1,2,3-triazole Analogues of Neolignans Veraguensin, Grandisin and Machilin G
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Sixteen 1,4-diaryl-1,2,3-triazole compounds derived from the natural products veraguensin, grandisin and machilin G were synthesized, with yields of 78-92percent. Biological activity tests against Leishmania amazonensis promastigotes showed that three of these compounds were the most active, with maximum inhibitory concentration (IC50 ) values of 1.1, 3.71 and 7.23 μM. One compound was highly active against Leishmania infantum, with an IC50 value of 5.2 μM, and one derivative showed an IC50 value of 28.6 μM against Trypanosoma cruzi trypomastigotes. Regarding structureactivity relationship (SAR), hybrid 1,2,3-triazolic compounds containing a methylenedioxy group, showed the best antileishmanial and antitrypanosomal activities.
- Cassamale, Tatiana B.,Costa, Eduarda C.,Carvalho, Diego B.,Cassemiro, Nadla S.,Tomazela, Carolina C.,Marques, Maria C. S.,Ojeda, Mariáh,Matos, Maria F. C.,Albuquerque, Sérgio,Arruda, Carla C. P.,Baroni, Adriano C. M.
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p. 1217 - 1228
(2016/08/25)
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- Synthesis of Oxazolidin-2-ones by Tandem Cyclization of Propargylic Alcohols and Phenyl Isocyanate Promoted by Silver Catalysts as π-Lewis Acids
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Highly Z-selective syntheses of oxazolidin-2-ones from propargylic alcohols containing internal alkynes and phenyl isocyanate were achieved by using a combination of silver acetate and N,N-dimethylaminopyridine. The catalytic system was applied to proparg
- Sekine, Kohei,Mawatari, Takanori,Yamada, Tohru
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supporting information
p. 2447 - 2450
(2015/10/19)
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- Rh/Cu-catalyzed multiple C-H, C-C, and C-N bond cleavage: Facile synthesis of pyrido[2,1-a]indoles from 1-(pyridin-2-yl)-1H-indoles and γ-substituted propargyl alcohols
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An unusual Rh/Cu-catalyzed synthesis of pyrido[2,1-a]indoles starting from 1-(pyridin-2-yl)-1H-indoles and γ-substituted propargyl alcohols was presented. The multi-step cascade transformations formally involve the cleavage of two C-H, three C-C, and one C-N bonds with concomitant construction of two C-H, four C-C, and one C-N bonds with excellent chemoselectivity in one-pot reaction.
- Li, Ting,Wang, Zhen,Zhang, Mingliang,Zhang, Hui-Jun,Wen, Ting-Bin
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supporting information
p. 6777 - 6780
(2015/04/22)
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- Ligand-Assisted Gold-Catalyzed Cross-Coupling with Aryldiazonium Salts: Redox Gold Catalysis without an External Oxidant
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Gold-catalyzed C(sp)-C(sp2) and C(sp2)-C(sp2) cross-coupling reactions are accomplished with aryldiazonium salts as the coupling partner. With the assistance of bpy ligand, gold(I) species were oxidized to gold(III) by diazonium without any external oxidants. Monitoring the reaction with NMR and ESI-MS provided strong evidence for the nitrogen extrusion followed by AuIII reductive elimination as the key step.
- Cai, Rong,Lu, Mei,Aguilera, Ellen Y.,Xi, Yumeng,Akhmedov, Novruz G.,Petersen, Jeffrey L.,Chen, Hao,Shi, Xiaodong
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p. 8772 - 8776
(2015/11/27)
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- Cyclization of Diaryl(hetaryl)alkynes under Selenobromination Conditions: Regioselectivity and Mechanistic Studies
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The cyclization of substituted diaryl(hetaryl)alkynes with in-situ-prepared SeBr4 has been achieved. The use of an alkene additive as a bromine scavenger gives simple access to functionalized benzo[b]selenophene and selenophenothiophene derivatives from commercially available or easily accessible starting materials. The reactions can be performed in air without the use of moisture-sensitive reagents, dry solvents, or an inert atmosphere. Mechanistic studies confirmed a regioselective anti 1,2-addition in the selenobromination step, and a subsequent electrophilic substitution in the aromatic ring to complete the cyclization. The cyclization of substituted diaryl(hetaryl)alkynes with in-situ-prepared SeBr4 has been achieved. The use of an alkene additive as a bromine scavenger gives simple access to functionalized benzo[b]selenophene and selenophenothiophene derivatives from commercially available or easily accessible starting materials.
- Paegle, Edgars,Belyakov, Sergey,Petrova, Marina,Liepinsh, Edvards,Arsenyan, Pavel
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supporting information
p. 4389 - 4399
(2015/07/27)
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- Tandem C-2 functionalization-intramolecular Azide-Alkyne 1,3-Dipolar Cycloaddition reaction: A convenient route to highly diversified 9H-Benzo[b]pyrrolo[1,2-g][1,2,3]triazolo[1,5-d][1,4]diazepines
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An efficient diversity-oriented synthetic approach to annulated 9H-benzo[b]pyrrolo[1,2-g][1,2,3]- triazolo[1,5-d][1,4]diazepines has been developed using a Sc(OTf)3-catalyzed two-component tandem C-2 functionalization- intramolecular azide-alky
- Hussain, Mohd. Kamil,Ansari, Mohd. Imran,Kant, Ruchir,Hajela, Kanchan
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supporting information
p. 560 - 563
(2014/04/03)
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- Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement and 1,4-addition to the resulting vinyl ketone
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Bi(OTf)3-catalyzed Meyer-Schuster rearrangement of electron-rich propargyl alcohols, followed by 1,4-addition of the resulting vinyl ketone, proceeded smoothly though Meyer-Schuster rearrangement of primary propargyl alcohols is rare. This tandem reaction can be extended to an intramolecular version, featuring a one-pot dihydroquinolone synthesis. (Chemical Equation Presented).
- Okamoto, Noriko,Sueda, Takuya,Yanada, Reiko
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p. 9854 - 9859
(2015/01/16)
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- An approach to the selenobromination of aryl(thienyl)alkynes: Access to 3-bromobenzo[b]selenophenes and selenophenothiophenes
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A novel approach for the cyclization of arylalkynes with selenium(IV) bromide prepared in situ has been elaborated. The use of an alkene additive as a bromine scavenger provides a convenient synthetic pathway for the synthesis of a wide variety of 3-bromobenzo[b]selenophenes. Reactions can be performed open to air without the use of moisture-sensitive reagents, anhydrous solvents, or an inert atmosphere. Selenobromination of ethynylthiophenes has been applied for the preparation of selenopheno[3,2-b]- and selenopheno[2,3-b]thiophenes. The molecular structures of representative derivatives have been confirmed by X-ray crystallographic analysis. The use of an alkene additive as a bromine scavenger under selenobromination conditions provides a convenient synthetic pathway for the synthesis of a wide variety of 3-bromobenzo[b]selenophenes in moderate to high yields. The reactions are not moisture-sensitive and do not require an inert atmosphere. Selenobromination of ethynylthiophenes enables the preparation of selenopheno[b]thiophenes. Copyright
- Paegle, Edgars,Belyakov, Sergey,Arsenyan, Pavel
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supporting information
p. 3831 - 3840
(2014/06/24)
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- Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions
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Two efficient protocols for the palladium-catalyzed synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides in the absence of copper were developed. A simple catalytic system consisting of Pd(OAc)2 and P(p-tol)3 using DBU as the base and THF as the solvent was found to be highly effective for the coupling reaction of 2-methyl-3-butyn-2-ol (4) with a wide range of aryl bromides in good to excellent yields. Analogously, the synthesis of aryl-2-methyl-3-butyn-2-ols was performed also through the decarboxylative coupling reaction of 4-hydroxy-4-methyl-2-pentynoic acid with aryl bromides, using a catalyst containing Pd(OAc)2 in combination with SPhos or XPhos in the presence of tetra-n-butylammonium fluoride (TBAF) as the base and THF as the solvent. Therefore, new efficient approaches to the synthesis of terminal acetylenes from widely available aryl bromides rather than expensive iodides and using 4 or propiolic acid rather than TMS-acetylene as inexpensive alkyne sources are described.
- Caporale, Andrea,Tartaggia, Stefano,Castellin, Andrea,De Lucchi, Ottorino
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supporting information
p. 384 - 393
(2014/03/21)
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- Palladium nanoparticles in glycerol: A versatile catalytic system for C-X bond formation and hydrogenation processes
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Palladium nanoparticles stabilised by tris(3-sulfophenyl)phosphine trisodium salt in neat glycerol have been synthesised and fully characterised, starting from both Pd(II) and Pd(0) species. The versatility of this innovative catalytic colloidal solution has been proved by its efficient application in C-X bond formation processes (X=C, N, P, S) and C-C multiple bond hydrogenation reactions. The catalytic glycerol phase could be recycled more than ten times, preserving its activity and selectivity. The scope of each of these processes has demonstrated the power of the as-prepared catalyst, isolating the corresponding expected products in yields higher than 90%. The dual catalytic behaviour of this glycerol phase, associated to the metallic nanocatalysts used in wet medium (molecular- and surface-like behaviour), has allowed attractive applications in one-pot multi-step transformations catalysed by palladium, such as C-C coupling followed by hydrogenation, without isolation of intermediates using only one catalytic precursor. Copyright
- Chahdoura, Faouzi,Pradel, Christian,Gomez, Montserrat
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supporting information
p. 3648 - 3660
(2014/01/06)
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- Glycerol - A non-innocent solvent for Rh-catalysed Pauson-Khand carbocyclisations
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Rh-catalysed carbocyclisations of the 1,6-enynes 1-8 efficiently gave bicyclo[3.3.0]octenones in neat glycerol. Unexpectedly, ligand-free [Rh(μ-OMe)(cod)]2 was highly selective. Moreover, TPPTS [tris(3-sulfonatophenyl)phosphane trisodium salt]
- Chahdoura, Faouzi,Dubrulle, Laurent,Fourmy, Kevin,Durand, Jerome,Madec, David,Gomez, Montserrat
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p. 5138 - 5144
(2013/10/22)
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- A copper-free, cross-coupling of terminal alkynes with hetaryl halides
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Substituted ethynyl heterocycles and heteroarylbutenynes are synthesized efficiently in good yields via a copper-free, cross-coupling reaction.
- Arsenyan, Pavel,Rubina, Kira,Vasiljeva, Jelena,Belyakov, Sergey
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p. 6524 - 6528
(2013/11/19)
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- Copper-catalyzed arylative meyer-schuster rearrangement of propargylic alcohols to complex enones using diaryliodonium salts
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Free choice: A copper-catalyzed arylative Meyer-Schuster rearrangement is described. The reaction is compatible with a range of substituted propargylic alcohols and diaryliodonium salts and delivers complex trisubstituted enone products selectively as the
- Collins, Beatrice S. L.,Suero, Marcos G.,Gaunt, Matthew J.
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supporting information
p. 5799 - 5802
(2013/06/27)
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- Copper-free oxime-palladacycle-catalyzed sonogashira alkynylation of deactivated aryl bromides and chlorides in water under microwave irradiation
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Palladium-catalyzed Heck alkynylation cross-coupling reactions between terminal alkynes and deactivated aryl chlorides and aryl bromides can be performed in the absence of copper cocatalyst with water as solvent at 130 °C under microwave irradiation. An oxime-derived chloro-bridged palladacycle is an efficient precatalyst for this transformation with 2- dicyclohexylphosphanyl-2',4',6'-triisopropylbiphenyl (XPhos as ancillary ligand, pyrrolidine as base, and SBDS as surfactant. All of the reactions can be performed under air and with reagent-grade chemicals under low loading conditions (0.1-1 mol-% Pd). Deactivated and hindered aryl bromides and chlorides are cross-coupled with terminal alkynes by using low catalyst loadings of an oxime palladacycle, pyrrolidine as base, sodium dodecylbenzenesulfonate (SBDS as surfactant, water as solvent, and microwave irradiation (40 W at 130 °C. Under these reaction conditions a wide array of tolane derivatives are prepared in moderate-to-good yields. Copyright
- Buxaderas, Eduardo,Alonso, Diego A.,Najera, Carmen
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supporting information
p. 5864 - 5870
(2013/09/23)
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- Synthesis of 2,3-diiodoindenes and their applications in construction of 13H-indeno[1,2-l]phenanthrenes
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A series of 2,3-diiodoindene were synthesized at first, and 13H-indeno[1,2-l]phenanthrenes were then constructed via a Suzuki coupling reaction and subsequently a Scholl reaction. Structures of synthesized compounds were fully characterized by 1H NMR, 13C NMR, and HRMS. Their photophysical properties, such as UV-vis and FL spectra were investigated, and electronic properties were theoretically calculated by the software of Gaussian 03. The results suggested that these modified indene and indenophenanthrene compounds might have potential applications as light emitting materials.
- Zhou, Chao,Chen, Xiaopeng,Lu, Ping,Wang, Yanguang
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supporting information; experimental part
p. 2844 - 2850
(2012/05/05)
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- Rapid catalyst evaluation for Sonogashira coupling in continuous flow
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Selection of the most appropriate catalyst for Pd-catalyzed Sonogashira coupling often requires time and resources. We applied a continuous flow device for rapid catalyst screening of 4 heterogeneous catalysts over 6 Sonogashira coupling reactions togethe
- Borcsek, Bernadett,Bene, Gyoergy,Szirbik, Gabor,Dorman, Gyoergy,Jones, Richard,Uerge, Laszlo,Darvas, Ferenc
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p. 186 - 195
(2013/09/24)
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- Photo-induced sonogashira C-C coupling reaction catalyzed by simple copper(I) chloride salt at room temperature
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The conventional thermal Sonogashira C-C coupling reaction requires the use of a palladium catalyst and a large amount of ligands. Although there were a few reports describing the use of inexpensive metal catalysts, such as, copper (Cu), iron (Fe), and nickel (Ni), for replacement of palladium (Pd) in the Sonogashira reactions, it was later questioned that the observed effects were due to ppb levels contamination of Pd present in the reagents used in the reactions. Herein, we report that simple copper(I) chloride (CuCl) salt, in the absence of Pd and ligands, can catalyze the Sonogashira reaction with high yields (80-99%) under blue LED light irradiation at room temperature. Control experiments show that no cross-coupling product was formed, when palladium(II) chloride (PdCl2) was used to replace CuCl as a catalyst. A series of electron-rich and electron-poor substituted aryl halides (bromides and iodides) as well as aryl- and alkylacetylenes are examined and the reaction mechanism is discussed.
- Sagadevan, Arunachalam,Hwang, Kuo Chu
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supporting information
p. 3421 - 3427
(2013/02/22)
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- Three types of products by carbon nucleophiles toward methoxyphenylacetylenic sulfones
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Methoxy-arylacetylenic sulfones were examined to react with various carbanion nucleophiles to result in the three types of products; thus, (i) nucleophiles (MeLi·LiBr, Vinyl MgBr, LiCH2CN) showed the α-addition, however, (ii) Li-CC-TMS afforded β-addition (conjugate addition) products. The (iii) displacement reaction through α-addition/ isomerization/trans-elimination was enhanced by the presence of ortho-methoxy group at high temperature. The heteroatom nucleophiles (nitrogen, oxygen or sulfur atom) in a protic solvent provided only conjugate addition products as reported.
- Cheng, Chia-Yi,Isobe, Minoru
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supporting information; experimental part
p. 9957 - 9965
(2012/02/06)
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- Simple and practical one-step synthesis of new 1,3-dienic δ-sultones from terminal alkynes and some synthetic applications of these compounds
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1,3-Dienic δ-sultones 4,6-diaryl-[1,2]oxathiine 2,2-dioxides were synthesized via a one-step reaction of arylalkynes with dioxane sulfotrioxide. The reactivity of various alkynes in this reaction was investigated. The resulting sultones were brominated with Br2 or N-bromosuccinimide regioselectively to sulfur and subsequently coupled with phenylacetylene using Sonogashira conditions.
- Gaitzsch, Jens,Rogachev, Victor,Metz, Peter,Filimonov, Victor D.,Zahel, Martin,Kataeva, Olga
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experimental part
p. 3 - 16
(2011/12/05)
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- Perfluoro-tagged, phosphine-free palladium nanoparticles supported on silica gel: Application to alkynylation of aryl halides, Suzuki-Miyaura cross-coupling, and Heck reactions under aerobic conditions
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The utilization of perfluoro-tagged palladium nanoparticles immobilized on fluorous silica gel through fluorous-fluorous interactions (Pd np-A/FSG) or through covalent bonding to silica gel (Pd np-B) in the alkynylation of aryl halides, in the Suzuki-Miyaura cross-coupling, as well as in the Heck reaction between methyl acrylate and aryl iodides is described. The reactions are carried out under aerobic and phosphine-free conditions with excellent to quantitative product yields in each case. The catalysts are easily recovered and reused several times without significant loss of activity. The alkynylation of aryl halides (under copper-free conditions) and the Suzuki-Miyaura cross-coupling are carried out in water. The Heck reaction of methyl acrylate with aryl iodides is best performed in MeCN. The utilization of Pdnp-B in the synthesis of 2,3-disubstituted indoles from 2-(alkynyl)trifluoroacetanilides and aryl halides is also reported.
- Bernini, Roberta,Cacchi, Sandro,Fabrizi, Giancarlo,Forte, Giovanni,Petrucci, Francesco,Prastaro, Alessandro,Niembro, Sandra,Shafir, Alexandr,Vallribera, Adelina
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supporting information; experimental part
p. 150 - 158
(2010/05/18)
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- Sonogashira reaction of aryl and heteroaryl halides with terminal alkynes catalyzed by a highly efficient and recyclable nanosized MCM-41 anchored palladium bipyridyl complex
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A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the reaction solution and re-used in further runs without significant loss of reactivity.
- Lin, Bo-Nan,Huang, Shao-Hsien,Wu, Wei-Yi,Mou, Chung-Yuan,Tsai, Fu-Yu
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experimental part
p. 9157 - 9173
(2011/02/27)
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- Alkynylation of aryl halides with perfluoro-tagged palladium nanoparticles immobilized on silica gel under aerobic, copper- and phosphine-free conditions in water
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The utilization of perfluoro-tagged palladium nanoparticles immobilized on fluorous silica gel through fluorous-fluorous interactions (Pd np-A/FSG) or linked to silica gel by covalent bonds (Pd np-B) in the alkynylation of terminal a
- Bernini, Roberta,Cacchi, Sandro,Fabrizi, Giancarlo,Forte, Giovanni,Petrucci, Francesco,Prastaro, Alessandro,Niembro, Sandra,Shafir, Alexandr,Vallribera, Adelina
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supporting information; scheme or table
p. 2270 - 2273
(2009/09/26)
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- Simple, convenient, and efficient synthesis of 2-aryl-substituted benzo[b]furans
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A simple, convenient, and efficient one-pot method for the preparation of benzofuran is reported. Sonogashira coupling reaction of aryl iodides with 2-methyl-3-butyn-2-ol was used as an acetylene source in the presence of Pd(PPh3)2Cl2 and CuI. Deprotection of the acetylene moiety in the same pot using a strong base and the second Sonogashira coupling/cyclization of and substituted o-iodophenols led to the formation of the appropriate benzo[b]furans. These protocols also can be used in the synthesis of natural products and indoles. Copyright Taylor & Francis Group, LLC.
- Jiang, Yong,Gao, Botao,Huang, Wenjuan,Liang, Yongmin,Huang, Guosheng,Ma, Yongxiang
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experimental part
p. 197 - 204
(2009/04/07)
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- Copper-free Sonogashira coupling in amine-water solvent mixtures
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Extensive study of different amine-water solvent mixtures was carried out for copper free Sonogashira coupling of aryl iodides. The influence of the palladium sources, ligands, amine-water ratio and further additives was also evaluated. Application of sec-butylamine-water mixture proved to be an excellent medium for rapid and efficient coupling of aryl-iodides at ambient temperature in the presence of PdCl2(PPh3)2 as catalyst.
- Komáromi, Anna,Tolnai, Gergely László,Novák, Zoltán
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supporting information; experimental part
p. 7294 - 7298
(2009/04/11)
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- Cyclopalladated ferrocenylimines: efficient catalysts for homocoupling and Sonogashira reaction of terminal alkynes
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A novel pathway for homocoupling of terminal alkynes has been described using cyclopalladated ferrocenylimine 1 or 2/CuI as catalyst in the air. This catalytic system could tolerate several functional groups. The palladacycle 2 in the presence of n-Bu4NBr as an additive could be applied to Sonogashira cross-coupling reaction of aryl iodides, aryl bromides, and some activated aryl chlorides with terminal alkynes under amine- and copper-free conditions, mostly to give moderate to excellent yields.
- Yang, Fan,Cui, Xiuling,Li, Ya-nan,Zhang, Jinli,Ren, Ge-rui,Wu, Yangjie
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p. 1963 - 1969
(2007/10/03)
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- Phosphorinanes as ligands for palladium-catalyzed cross-coupling chemistry
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(Chemical Equation Presented) Phosphorinanes are presented as a class of phosphine ligand suitable for organopalladium cross-coupling chemistry. Prepared via a direct double Michael addition of a monoalkyl- or arylphosphine to phorone followed by a Wolf-K
- Brenstrum, Tim,Clattenburg, Julie,Britten, James,Zavorine, Serguei,Dyck, Jeff,Robertson, Alan J.,McNulty, James,Capretta, Alfredo
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p. 103 - 105
(2007/10/03)
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- New activators for the coupling reaction of terminal alkynes with organic halides
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Cross-coupling reactions of terminal alkynes with organic halides catalyzed by palladium(0) or palladium(0)/Cu(I) take place in the presence of several activators, such as silver(I) oxide, tetrabutylammonium fluoride (TBAF), and tetrabutylammonium hydroxi
- Ahmed, Mohamed S. Mohamed,Sekiguchi, Akitoshi,Shimada, Tomohiro,Kawashima, Jun,Mori, Atsunori
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p. 327 - 330
(2007/10/03)
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- Ferrocenyl-palladium complexes in cross-coupling reactions: A comparative study
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Ferrocenecarboxaldehyde hydrazones were converted into palladium complexes on treatment with sodium tetrachloropalladate. The substitution pattern of the ferrocenylhydrazones was found to have a marked influence on the mode the palladium was attached to the organic moiety. The catalytic activity of the new palladium complexes in cross-coupling reactions was examined in detail, and it was compared with conventional catalyst systems.
- Nagy, Tibor Zs.,Csámpai, Antal,Kotschy, András
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p. 9767 - 9774
(2007/10/03)
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- A convenient high activity catalyst for the Sonogashira coupling of aryl bromides
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A mixture of Na2PdCl4, CuI and (t-Bu) 3PH+BF4- (molar ratio 4:3:8) dispersed in H2N(i-Pr)2 Br can be used as a "single source" precatalyst for the Sonogashira coupling of aryl bromides with various aryl- and alkylacetylenes in HN(i-Pr)2 solvent. Arylacetylenes require just 0.005 mol % of Pd catalyst at 80°C, with TOFs ranging between 3,200 and 10,000 h-1.
- Koellhofer, Axel,Plenio, Herbert
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p. 1295 - 1300
(2007/10/03)
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- A simple catalyst system for the palladium-catalyzed coupling of aryl halides with terminal alkynes
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A convenient catalyst system consisting of Pd(OAc)2, PPh 3, K3PO4 and DMSO was found to be effective for the coupling reaction of aryl halides with terminal alkynes as well as the deacetonative coupling reaction using a 4-aryl-2-methylbut-3-yn-2-ol as a terminal alkyne precursor. An iminophosphine as a ligand worked more effectively for some combination of substrates than triphenylphosphine.
- Shirakawa, Eiji,Kitabata, Takaaki,Otsuka, Hidehito,Tsuchimoto, Teruhisa
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p. 9878 - 9885
(2007/10/03)
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- Palladium complexes of 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6- phosphaadamantane: Synthesis, crystal structure and use in the Suzuki and Sonogashira reactions and the α-arylation of ketones
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Palladium complexes of 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6- phosphaadamantane were prepared and characterized with Pd[1,3,5,7-tetramethyl-2, 4,8-trioxa-6-phenyl-6-phosphaadamantane]2·dba shown to be an effective catalyst for use in the
- Adjabeng, George,Brenstrum, Tim,Frampton, Christopher S.,Robertson, Al J.,Hillhouse, John,McNulty, James,Capretta, Alfredo
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p. 5082 - 5086
(2007/10/03)
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