- Zinc-Catalysed Hydroboration of Terminal and Internal Alkynes
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A regioselective hydroboration of alkynes has been developed by using commercially available zinc triflate as a catalyst, in the presence of catalytic amount of NaBHEt3. The reaction tolerates a wide range of terminal alkynes having several synthetically useful functional groups and proceeds regioselectively to furnish hydroborated products in moderate to excellent yields. This system shows moderate chemoselectivity towards terminal C≡C bond over terminal and internal C=C bond and internal C≡C bond.
- Mandal, Souvik,Mandal, Sayantan,Geetharani
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p. 4553 - 4556
(2019/08/20)
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- Chemoselective Synthesis of 1,1-Disubstituted Vinyl Triflates from Terminal Alkynes Using TfOH in the Presence of TMSN3
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1,1-Disubstituted vinyl triflates are synthesized by direct hydrotriflation of terminal alkynes employing a combination of TfOH and TMSN3 in DCM at room temperature. Interestingly, under these conditions, only terminal alkynes were selectively
- Tummatorn, Jumreang,Punjajom, Kunlayanee,Rodphon, Warabhorn,Ruengsangtongkul, Sureeporn,Chaisan, Nattawadee,Lumyong, Kanyapat,Thongsornkleeb, Charnsak,Nimnual, Phongprapan,Ruchirawat, Somsak
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supporting information
p. 4694 - 4697
(2019/06/27)
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- A one-pot method for the synthesis of phenylalkynyl-substituted terminal alkynes by deprotection/stannylation followed by a Migita-Kosugi-Stille coupling
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A practical one-pot approach for the synthesis of arylalkynyl-substituted terminal alkynes has been developed through a deprotection/ stannylation of a phenylethynyl phosphine oxide followed by Migita-Kosugi-Stille coupling, avoiding the longer synthetic route involving repeated deprotection/Sonogashira coupling. Other features of this approach include mild reaction conditions, excellent yields, facile isolation of products and wide functional group tolerance.
- Peng, Li-Fen,Wang, Bing-Hao,Wang, Ming,Tang, Zi-Long,Jiang, Yan-Zi,Jiao, Yin-Chun,Xu, Xin-Hua
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p. 235 - 238
(2018/06/27)
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- Stereospecific Nucleophilic Substitution with Arylboronic Acids as Nucleophiles in the Presence of a CONH Group
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Stereospecific nucleophilic substitution was achieved for the first time with arylboronic acids as nucleophiles. This transition-metal-free coupling between chiral α-aryl-α-mesylated acetamides and arylboronic acids provided access to a series of chiral α,α-diaryl acetamides with excellent enantioselectivity and moderate to good yields. The CONH functionality proved to be crucial for bridging the reactants and promoting the reaction. Efficient syntheses of a cannabinoid CB1 receptor ligand, the antidepressant (S)-diclofensine, and a key chiral building block of the inhibitor implitapide were successfully accomplished by using this method.
- Tian, Duanshuai,Li, Chengxi,Gu, Guoxian,Peng, Henian,Zhang, Xumu,Tang, Wenjun
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supporting information
p. 7176 - 7180
(2018/05/29)
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- Synthesis of plasmodione metabolites and 13C-enriched plasmodione as chemical tools for drug metabolism investigation
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Malaria is a tropical parasitic disease threatening populations in tropical and sub-tropical areas. Resistance to antimalarial drugs has spread all over the world in the past 50 years, thus new drugs are urgently needed. Plasmodione (benzylmenadione series) has been identified as a potent antimalarial early lead drug, acting through a redox bioactivation on asexual and young sexual blood stages. To investigate its metabolism, a series of plasmodione-based tools, including a fully 13C-labelled lead drug and putative metabolites, have been designed and synthesized for drug metabolism investigation. Furthermore, with the help of UHPLC-MS/MS, two of the drug metabolites have been identified from urine of drug-treated mice.
- Feng, Liwen,Lanfranchi, Don Antoine,Cotos, Leandro,Cesar-Rodo, Elena,Ehrhardt, Katharina,Goetz, Alice-Anne,Zimmermann, Herbert,Fenaille, Fran?ois,Blandin, Stephanie A.,Davioud-Charvet, Elisabeth
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p. 2647 - 2665
(2018/04/27)
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- Nickel-Catalyzed Highly Regioselective Hydrocyanation of Terminal Alkynes with Zn(CN)2 Using Water as the Hydrogen Source
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The first efficient and general nickel-catalyzed hydrocyanation of terminal alkynes with Zn(CN)2 in the presence of water has been developed. The reaction provides a regioselective protocol for the synthesis of functionalized vinyl nitriles with a range of structural diversity under mild reaction conditions while obviating use of the volatile and hazardous reagent of HCN. Deuterium-labeling experiments confirmed the role of water as the hydrogen source in this hydrocyanation reaction.
- Zhang, Xingjie,Xie, Xin,Liu, Yuanhong
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p. 7385 - 7389
(2018/06/11)
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- MONOMER, POLYMER, COMPENSATION FILM, OPTICAL FILM, AND DISPLAY DEVICE
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A monomer represented by Chemical Formula 1-1 wherein in Chemical Formula 1-1, Z, L1, L2, R1 to R6, n, m, p, and a to f are the same as defined in the detailed description.
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- Reversible Hydride Transfer to N,N′-Diarylimidazolinium Cations from Hydrogen Catalyzed by Transition Metal Complexes Mimicking the Reaction of [Fe]-Hydrogenase
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[Fe]-hydrogenase is a key enzyme involved in methanogenesis and facilitates reversible hydride transfer from H2 to N5,N10-methenyltetrahydromethanopterin (CH-H4MPT+). In this study, a reaction system was developed to model the enzymatic function of [Fe]-hydrogenase by using N,N′-diphenylimidazolinium cation (1+) as a structurally related alternative to CH-H4MPT+. In connection with the enzymatic mechanism via heterolytic cleavage of H2 at the single metal active site, several transition metal complex catalysts capable of such activation were utilized in the model system. Reduction of 1[BF4] to N,N′-diphenylimidazolidine (2) was achieved under 1 atm H2 at ambient temperature in the presence of an equimolar amount of NEt3 as a proton acceptor. The proposed catalytic pathways involved the generation of active hydride complexes and subsequent intermolecular hydride transfer to 1+. The reverse reaction was accomplished by treatment of 2 with HNMe2Ph+ as the proton source, where [(ν5-C5Me5)Ir{(p-MeC6H4SO2)NCHPhCHPhNH}] was found to catalyze the formation of 1+ and H2 with high efficiency. These results are consistent with the fact that use of 2,6-lutidine in the forward reaction or 2,6-lutidinium in the reverse reaction resulted in incomplete conversion. By combining these reactions using the above Ir amido catalyst, the reversible hydride transfer interconverting 1+/H2 and 2/H+ was performed successfully. This system demonstrated the hydride-accepting and hydride-donating modes of biologically relevant N-heterocycles coupled with proton concentration. The influence of substituents on the forward and reverse reactivities was examined for the derivatives of 1+ and 2 bearing one para-substituted N-phenyl group.
- Hatazawa, Masahiro,Yoshie, Naoko,Seino, Hidetake
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p. 8087 - 8099
(2017/07/22)
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- One-pot transformation of Ph2P(O)-protected ethynes: Deprotection followed by transition metal-catalyzed coupling
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Ph2P(O)-protected ethynes were successfully transformed to arylethynes in one-pot manner through t-BuOK-catalyzed deprotection followed by Sonogashira coupling with aryl halide. The arylethynes were obtained similarly by Ph2P(O)-deprotection, stannylation of the resulting terminal ethynes, and Migita-Kosugi-Stille coupling. Deprotection followed by intramolecular Eglinton coupling could be carried out in one-pot to provide cyclic butadiynes.
- Peng, Lifen,Xu, Feng,Suzuma, Yoshinori,Orita, Akihiro,Otera, Junzo
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p. 12802 - 12808
(2014/01/17)
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- Molecular daisy chains: Synthesis and aggregation studies of an amphiphilic molecular rod
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A water-soluble cyclophane as the loop subunit, monofunctionalized with a molecular rod, has been synthesized to introduce a new binding motif for mechanically interlinked oligomers. It has been demonstrated that this hermaphroditic compound forms [c2]dai
- Rotzler, Juergen,Drayss, Sylvie,Hampe, Oliver,Haeussinger, Daniel,Mayor, Marcel
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p. 2089 - 2101
(2013/04/10)
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- Variable-gap conjugated oligomers grafted to CdSe nanocrystals
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Three linear asymmetrically functionalized conjugated molecules composed of five or six aromatic rings were synthesized, bearing a terminal phosphonic acid group, with the objective of enabling their grafting onto inorganic CdSe nanocrystals. These chromo
- Stalder, Romain,Xie, Dongping,Zhou, Renjia,Xue, Jiangeng,Reynolds, John R.,Schanze, Kirk S.
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p. 3143 - 3152
(2015/03/18)
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- Closely stacked oligo(phenylene ethynylene)s: Effect of π-stacking on the electronic properties of conjugated chromophores
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In this work, a bicyclo[4.4.1]undecane scaffold is used to hold oligo(phenylene ethynylene) units in a cofacially stacked arrangement along the entire length of the conjugated units. We study the impact that the resulting strong interchain interactions ha
- Jagtap, Subodh P.,Mukhopadhyay, Sukrit,Coropceanu, Veaceslav,Brizius, Glen L.,Bredas, Jean-Luc,Collard, David M.
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supporting information; experimental part
p. 7176 - 7185
(2012/06/15)
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- A rapid and efficient synthetic route to terminal arylacetylenes by tetrabutylammonium hydroxide- and methanol-catalyzed cleavage of 4-aryl-2-methyl-3-butyn-2-ols
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Tetrabutylammonium hydroxide with methanol as an additive was found to be a highly active catalyst for the cleavage of 4-aryl-2-methyl-3-butyn-2-ols. The reaction was performed at 55-75 °C and gave terminal arylacetylenes in good to excellent yields within several minutes. Compared with the usual reaction conditions (normally >110 °C, several hours), this novel catalyst system can dramatically decrease the reaction time under much milder conditions.
- Li, Jie,Huang, Pengcheng
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p. 426 - 431
(2011/06/11)
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- Fluoro-substituted phenyleneethynylenes: Acetylenic n-type organic semiconductors
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Fluoro-substituted phenyleneethynylenes are synthesized by Sonogashira coupling and acetylide-nucleophilic substitution of fluorobenzenes. Fluoro-substitution of benzenes enables deep LUMO potential, and CF 3-substitution provides high electron
- Matsuo, Daisuke,Yang, Xin,Hamada, Akiko,Morimoto, Kyo,Kato, Takuji,Yahiro, Masayuki,Adachi, Chihaya,Orita, Akihiro,Otera, Junzo
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p. 1300 - 1302
(2011/02/17)
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- Geometrically homogenous series of covalently linked zinc/free-base porphyrin dimers of varying length; design, synthesis and characterization
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Singlet excitation energy transfer, SEET, can be mediated by a bridge, connecting an energy donor and acceptor, via a superexchange mechanism. The mediation efficiency depends on the energy difference between the first excited states of the donor and the bridge, ΔEDB, as well as the donor-acceptor distance, RDA. We have previously constructed a series of donor-bridge-acceptor, D-B-A, systems that allowed us to study how SEET depends on ΔEDB. To expand this study into a second dimension, the distance dependence, a new series of D-B-A systems were constructed. This series was based on the same zinc/free-base porphyrin couple as the donor-acceptor pair in the previous series. Their relative orientation was also retained. In contrast to our first series, the bridges in the latter were of varying length. The bridges were oligo(phenyleneethynylene)phenylene (OPE) structures and the length was systematically changed by increasing the number of phenyleneethynylene units from 1 to 4. To obtain high quality samples, the D-B-A systems were assembled by a building block approach where the zinc and free-base porphyrins were introduced separately using Heck alkynylations. The performance of the OPE structure as a mediator and scaffold is discussed in terms of singlet excited state energies and flexibility. For the first time, when combining the topical D-B-A systems with our previous subset, a homogeneous series of D-B-A systems has been synthesized that allows for studies of both the distance dependence and the energy difference dependence of SEET. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Ljungdahl, Thomas,Pettersson, Karin,Albinsson, Bo,Martensson, Jerker
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p. 3087 - 3096
(2007/10/03)
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- New fluorophores with rod-shaped polycyano π-conjugated structures: Synthesis and photophysical properties
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Novel rod-shaped polycyano-oligo(phenyleneethynylene)s were synthesized by Pd cross-coupling reaction. Polycyano groups were found to greatly improve the emission efficiency (Φf) of OPEs. By the end donor modification, we achieved the creation of very intense blue light-emitting fluorophore with the SMe group (Φf) = 0.972, log ε 4.89, λ em 455 nm) and very intense yellow light-emitting fluorophore with the NMe2 group (Φf = 0.999, log ε 4.75, λem 555 nm). Contrasting Φf solvent dependency of 6 and 7 and a linear relationship between Φf and σp-X over the whole region of σp-X were also found.
- Yamaguchi, Yoshihiro,Ochi, Takanori,Wakamiya, Tateaki,Matsubara, Yoshio,Yoshida, Zen-Ichi
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p. 717 - 720
(2007/10/03)
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- Multiple self-assembled nanostructures from an oligo(p-phenyleneethynylene) containing rod-coil-rod triblock copolymer
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Induced by systematic variation of the initial polymer concentration in toluene, various morphologies of aggregates including vesicles, spheres, onion-like structures, and worm-like fibers from a rod-coil-rod triblock copolymer, oligo(p-phenyleneethynylene)-polystyrene-oligo(p-phenyleneethynylene) , were observed by transmission electron microscopy. The Royal Society of Chemistry 2005.
- Li, Kun,Wang, Qing
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p. 4786 - 4788
(2008/01/27)
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- Light-emitting efficiency tuning of rod-shaped π conjugated systems by donor and acceptor groups
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In view of the increasing importance of highly efficient light-emitting materials in chemistry, biological science, and materials science, we investigated the light-emitting efficiency tuning of rod-shaped oligo(p-phenylene ethynylene)s (OPEs, trimeric to pentameric systems) by donor and acceptor groups, so that they emit the very intense fluorescence (Φf ≈ 1.0, log ε ≈ 5) at 460 nm as the desired wavelength region. This goal was achieved by side modification by MeO (donor) groups and end modification by a CN-substituted benzene ring or CF3-substituted pyridine ring (acceptor) of tetrameric p-phenylene ethynylene rod-shaped molecules (Φf = 0.96, λem = 458 nm, log ε = 4.96 for the former and Φf = 0.99, λem = 459 nm, log ε = 4.92 for the latter). The high Φf values for 11 and 12 are interpreted in terms of kr (radiative rate constant) and kd (radiationless rate constant). The linear relationship with a positive slope between Φf and the Hammett σ constant was found for the first time. It is found that kd rather than kr varies with σp-X. The photophysical properties (Φf, λem, λabs, log ε) were not so altered with the solvent polarity, which could be explained by the dipole moments in the excited and ground states. The results would be valuable for the molecular design of highly efficient light-emitting materials. Copyright
- Yamaguchi, Yoshihiro,Tanaka, Takahiro,Kobayashi, Shigeya,Wakamiya, Tateaki,Matsubara, Yoshio,Yoshida, Zen-Ichi
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p. 9332 - 9333
(2007/10/03)
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- Synthesis of nitrile-terminated potential molecular electronic devices
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Several potential molecular devices have been synthesized consisting of oligo(phenylene ethynylene) (OPE) backbones containing a terminal nitrile group alligator clip as a means of attachment to a metal surface. The synthesis of four new nitrile-containing OPEs is discussed, including an improved synthesis of an intermediate used in our prior production of OPEs containing acetate-protected thiol alligator clips.
- Dirk, Shawn M.,Tour, James M.
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p. 287 - 293
(2007/10/03)
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- Combinatorial synthesis of oligo(phenylene ethynylene)s
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The combinatorial synthesis of oligo(phenylene ethynylene) tetramers, both in solution and on solid support, is described. These products are of interest for molecular electronics applications. An iterative sequence, coupling of aryl halides to alkynes under Sonogashira conditions, was used. Five monomers functionalized with electron-donating or electron-withdrawing groups were synthesized, and used to generate a library of 25 trimers in a solution-phase based process. A library of 24 tetramers was prepared by subsequent protodesilylation and coupling with the alligator clip 4-iodo-1-thioacetylbenzene. The solution-phase based sequence was successfully adapted to a higher yielding directed split-and-pool solid-phase process, with average yields of 78-86% for each step over seven steps. A triazene linker group was used to attach the starting monomer to the polymer beads. At the completion of the solid-phase-based process, traceless cleavage of trimers from the resin was achieved by sonication of the resin in 10% HCl/THF solution. The released products were then poised for the final step in the sequence, attachment of the alligator clip.
- Hwang, Jiunn-Jye,Tour, James M.
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p. 10387 - 10405
(2007/10/03)
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- Synthesis and preliminary testing of molecular wires and devices
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Presented here are several convergent synthetic routes to conjugated oligo(phenylene ethynylene)s. Some of these oligomers are free of functional groups, while others possess donor groups, acceptor groups, porphyrin interiors, and other heterocyclic interiors for various potential transmission and digital device applications. The syntheses of oligo(phenylene ethynylene)s with a variety of end groups for attachment to numerous metal probes and surfaces are presented. Some of the functionalized molecular systems showed linear, wire-like, current versus voltage (I(V)) responses, while others exhibited nonlinear I(V) curves for negative differential resistance (NDR) and molecular random access memory effects. Finally, the syntheses of functionalized oligomers are described that can form self-assembled monolayers on metallic electrodes that reduce the Schottky barriers. Information from the Schottky barrier studies can provide useful insight into molecular alligator clip optimizations for molecuar electronics.
- Tour, James M.,Rawlett, Adam M.,Kozaki, Masatoshi,Yao, Yuxing,Jagessar, Raymond C.,Dirk, Shawn M.,Price, David W.,Reed, Mark A.,Zhou, Chong-Wu,Chen, Jia,Wang, Wenyong,Campbell, Ian
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p. 5118 - 5134
(2007/10/03)
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- Self-assembly of quinodimethanes through covalent bonds. Part III. Investigations on the preparation of nanostructures
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As part of our studies on the tetramerization of quinodimethane 1 to the macrocyclic compound 2, the influence of substituents on this reaction was investigated. It was found that a large range of substituents such as 2- phenylethyl, 2-(4-methoxyphenyl)et
- Ipaktschi, Junes,Hosseinzadeh, Rahman,Schlaf, Peter,Eckert, Thomas
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p. 1224 - 1238
(2007/10/03)
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- Selective and efficient access to ortho, meta and para ring-substituted phenylacetylene derivatives R-[C≡C-C6H4](x)-Y (Y:H, NO2, CN, I, NH2)
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ortho, meta and para isomers of iodo and amino ring-substituted phenylacetylene as well as rod-like arylacetylene derivatives were prepared by a simple synthetic route involving three consecutive reactions: the palladium-catalysed carbon-carbon bond forma
- Lavastre, Olivier,Cabioch, Sandrine,Dixneuf, Pierre H.,Vohlidal, Jiri
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p. 7595 - 7604
(2007/10/03)
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- Preparation of New Complexing Agents Containing a Highly Conjugated Ethynylated Pyridine Subunit
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Highly conjugated 4-ethynyl derivatives of 2,6-pyridinedicarboxylic acid and 2,6-bispyridine have been prepared using coupling reactions between 4-bromo- and 4-ethylnyl-pyridines and acetylenes in the presence of a small
- Haenninen, Elina,Takalo, Harri,Kankare, Jouko
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p. 614 - 619
(2007/10/02)
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