- Preparation and catalytic performance of a molecularly imprinted Pd complex catalyst for Suzuki cross-coupling reactions
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A SiO2-supported molecularly imprinted Pd complex with SiO2-matrix overlayers was prepared as a Suzuki cross-coupling catalyst. A ligand on the supported Pd complex was used as a molecular imprinting template to create the reaction space. The structures of the supported and molecularly imprinted Pd complexes on SiO2 were determined by solid-state MAS 13C, 29Si, and 31P NMR; diffuse reflectance UV/vis; XPS; and Pd K-edge XAFS. The catalytic performance of the molecularly imprinted Pd complex catalyst was very different for various combinations of aryl iodides and arylboronic acids. Reactants with bulky substituent groups were hindered on the imprinted catalyst in Suzuki cross-coupling reactions.
- Muratsugu, Satoshi,Maity, Niladri,Baba, Hiroshi,Tasaki, Masahiro,Tada, Mizuki
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- Formal Allylation and Enantioselective Cyclopropanation of Donor/Acceptor Rhodium(II) Azavinyl Carbenes
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A highly efficient formal allylation of dihydronaphthotriazoles with alkenes under rhodium(II) catalysis is reported. Various allyl dihydronaphthalene derivatives were furnished via rhodium(II) azavinyl carbenes with moderate to good yields and excellent chemoselectivity. When monosubstituted alkenes are used, cyclopropanation occurs and good to excellent enantioselectivities have been achieved. Particularly noteworthy is the allylic C(sp2)-H activation instead of traditional C(sp3)-H activation in the formal allylation process.
- Liu, Zhili,Chen, Lianfen,Zhu, Dong,Zhu, Shifa
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supporting information
p. 1275 - 1279
(2021/02/20)
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- MnBr2 catalyzed regiospecific oxidative Mizoroki-Heck type reaction
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Herein, we report an unprecedented regiospecific oxidative Mizoroki-Heck type reaction for the synthesis of ɑ-difluoromethyl homoallylic alcohols. The reaction shows broad substrate scopes and high functional group tolerance. Late-stage functionalization of complex biologically active molecules demonstrates the synthetic potential of this transformation. Mechanistic study supports the involvement of MnBr2 catalyzed radical 1,2-silyl transfer.
- Chen, Xiang,Chen, Yi-Hung,Liu, Shanshan,Shen, Xiao,Zhu, Zhihong
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supporting information
(2021/11/27)
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- Highly Enantioselective Iridium-Catalyzed Hydrogenation of 2-Aryl Allyl Phthalimides
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The iridium-catalyzed asymmetric hydrogenation of 2-aryl allyl phthalimides to afford enantioenriched β-aryl-β-methyl amines is presented. Recently developed Ir-MaxPHOX catalysts are used for this enantioselective transformation. The mild reaction conditions and the feasible removal of the phthalimido group makes this catalytic method easily scalable and of great interest to afford chiral amines. The importance of this new methodology is exemplified by the formal synthesis of (R)-Lorcaserin, OTS514, and enantiomerically enriched 3-methyl indolines.
- Cabré, Albert,Romagnoli, Elia,Martínez-Balart, Pol,Verdaguer, Xavier,Riera, Antoni
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supporting information
p. 9709 - 9713
(2019/11/19)
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- Synthesis of 2-Substituted Propenes by Bidentate Phosphine-Assisted Methylenation of Acyl Fluorides and Acyl Chlorides with AlMe3
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Bidentate phosphine-assisted methylenation of acyl fluorides and acyl chlorides with substituted with aryl, alkenyl, and alkyl groups trimethylaluminum afforded an array of 2-substituted propene derivatives. The addition of a catalytic amount of DPPM increased an efficiency of the reactions. Trimethylaluminum as the methylenation reagent not only eliminates the presynthesis of methylene transfer reagent, but provides an efficient method for the synthesis of a series of 2-substituted propenes.
- Wang, Xiu,Wang, Zhenhua,Asanuma, Yuya,Nishihara, Yasushi
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supporting information
p. 3640 - 3643
(2019/05/17)
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- Iridium-Catalyzed Isomerization of N-Sulfonyl Aziridines to Allyl Amines
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The Crabtree's reagent catalyzes the isomerization of N-sulfonyl 2,2-disubstituted aziridines to allyl amines. The selectivity of allyl amine vs imine is very high (up to 99/1). The unprecedented isomerization takes place in mild conditions without activation of the catalyst by hydrogen. The mechanism has been studied computationally by DFT calculations; instead of the usual hydrogenation of COD, the catalytic species is formed by a loss of the pyridine ligand. Approaching of aziridine to this unsaturated species leads to a carbocation intermediate through a low energy barrier. A metal-mediated tautomerization involving sequentially γ-H elimination and N-H reductive elimination affords selectively the allyl amine. The readiness of the CγH bond to participate in the H elimination step accounts for the selectivity toward the allyl amine product.
- Cabré, Albert,Sciortino, Giuseppe,Ujaque, Gregori,Verdaguer, Xavier,Lledós, Agustí,Riera, Antoni
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supporting information
p. 5747 - 5751
(2018/09/21)
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- A Copper Catalyst with a Cinchona-Alkaloid-Based Sulfonamide Ligand for Asymmetric Radical Oxytrifluoromethylation of Alkenyl Oximes
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A copper-catalyzed asymmetric radical oxytrifluoromethylation of alkenyl oxime and Togni's reagent has been successfully developed, thereby providing straightforward access to CF3-containing isoxazolines bearing α-tertiary stereocenters with excellent yield and enantioselectivity. The key to success is the rational design of cinchona-alkaloid-based sulfonamides as neutral/anionic hybrid ligands to effectively control the stereochemistry in copper-catalyzed reactions involving free alkyl radical species. The utility of this method is illustrated by efficient transformation of the products into useful chiral CF3-containing 1,3-aminoalcohols.
- Li, Xi-Tao,Gu, Qiang-Shuai,Dong, Xiao-Yang,Meng, Xiang,Liu, Xin-Yuan
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supporting information
p. 7668 - 7672
(2018/05/30)
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- Mild Ring-Opening 1,3-Hydroborations of Non-Activated Cyclopropanes
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The Brown hydroboration reaction, first reported in 1957, is the addition of B?H across an olefin in an anti-Markovnikov fashion. Here, we solved a long-standing problem on mild 1,3-hydroborations of non-activated cyclopropanes. A three-component system including cyclopropanes, boron halides, and hydrosilanes has been developed for borylative ring-opening of cyclopropanes following the anti-Markovnikov rule, under mild reaction conditions. Density functional theory (M06-2X) calculations show that the preferred pathway involves a cationic boron intermediate which is quenched by hydride transfer from the silane.
- Wang, Di,Xue, Xiao-Song,Houk, Kendall N.,Shi, Zhuangzhi
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supporting information
p. 16861 - 16865
(2018/11/27)
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- Copper-catalyzed radical oxytrifluoromethylation of alkenyl oximes at ambient temperature
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A mild and efficient copper-catalyzed radical oxytrifluoromethylation reaction of alkenyl oximes was successfully developed. The method provides a straightforward access to a wide range of CF3-containing isoxazolines in good to excellent yields.
- Li, Xi-Tao,Lv, Ling,Gu, Qiang-Shuai,Liu, Xin-Yuan
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supporting information
p. 6041 - 6046
(2018/09/11)
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- Alkene Hydrogenations by Soluble Iron Nanocluster Catalysts
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The replacement of noble metal technologies and the realization of new reactivities with earth-abundant metals is at the heart of sustainable synthesis. Alkene hydrogenations have so far been most effectively performed by noble metal catalysts. This study reports an iron-catalyzed hydrogenation protocol for tri- and tetra-substituted alkenes of unprecedented activity and scope under mild conditions (1–4 bar H2, 20 °C). Instructive snapshots at the interface of homogeneous and heterogeneous iron catalysis were recorded by the isolation of novel Fe nanocluster architectures that act as catalyst reservoirs and soluble seeds of particle growth.
- Gieshoff, Tim N.,Chakraborty, Uttam,Villa, Matteo,Jacobi von Wangelin, Axel
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supporting information
p. 3585 - 3589
(2017/03/21)
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- Iron-Catalyzed Acyloxyalkylation of Styrenes Using Hypervalent Iodine Reagents
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Iron-catalyzed acyloxyalkylation of styrene derivatives using hypervalent iodine reagents was achieved. The acyloxyalkylation reaction proceeded using various types of styrenes and hypervalent iodine reagents. The acyloxyalkylated products were obtained in moderate to good yields without loss of the functional groups. The reaction proceeded via the formation of radical species derived from hypervalent iodine reagents by decarboxylation.
- Wang, Zijia,Kanai, Motomu,Kuninobu, Yoichiro
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supporting information
p. 2398 - 2401
(2017/05/12)
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- Visible light-promoted dihydroxylation of styrenes with water and dioxygen
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An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
- Yang, Bo,Lu, Zhan
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supporting information
p. 12634 - 12637
(2017/12/02)
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- Mn-Catalyzed Highly Efficient Aerobic Oxidative Hydroxyazidation of Olefins: A Direct Approach to β-Azido Alcohols
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(Chemical Equation Presented). An efficient Mn-catalyzed aerobic oxidative hydroxyazidation of olefins for synthesis of β-azido alcohols has been developed. The aerobic oxidative generation of azido radical employing air as the terminal oxidant is disclosed as the key process for this transformation. The reaction is appreciated by its broad substrate scope, inexpensive Mn-catalyst, high efficiency, easy operation under air, and mild conditions at room temperature. This chemistry provides a novel approach to high value-added β-azido alcohols, which are useful precursors of aziridines, β-amino alcohols, and other important N- and O-containing heterocyclic compounds. This chemistry also provides an unexpected approach to azido substituted cyclic peroxy alcohol esters. A DFT calculation indicates that Mn catalyst plays key dual roles as an efficient catalyst for the generation of azido radical and a stabilizer for peroxyl radical intermediate. Further calculation reasonably explains the proposed mechanism for the control of C-C bond cleavage or for the formation of β-azido alcohols.
- Sun, Xiang,Li, Xinyao,Song, Song,Zhu, Yuchao,Liang, Yu-Feng,Jiao, Ning
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supporting information
p. 6059 - 6066
(2015/05/27)
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- Method for synthesizing (E)-Anethol and Related Compounds By Cross Coupling Reaction of Potassium alllyltrifluroborate and 4-bromoanisole and aryl halides
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Methods of producing substituted and non-substituted beta-methyl styrene by a cross-coupling reaction are provided. The disclosure also provides for methods of preparing (E)-Anethol and related compounds by a cross coupling reaction of potassium allyltrifluoroborate and 4-bromoanisole and aryl halides. Compounds, compositions, and methods of treating disorders utilizing beta-methyl styrene are also provided.
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Page/Page column 4
(2012/01/15)
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- Highly enantioselective hydrogenation of β,β-disubstituted nitroalkenes
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Building the building blocks: A highly enantioselective hydrogenation of ?-aryl-?-alkyl disubstituted nitroalkenes 1 has been developed. This method results in enantiomerically pure nitroalkanes 2, which are versatile precursors for chemical synthesis.
- Li, Shengkun,Huang, Kexuan,Cao, Bonan,Zhang, Jiwen,Wu, Wenjun,Zhang, Xumu
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supporting information; experimental part
p. 8573 - 8576
(2012/09/10)
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- Design, synthesis, and biological evaluation of novel diarylalkyl amides as TRPV1 antagonists
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We have developed a new class of diarylalkyl amides as novel TRPV1 antagonists. They exhibited potent 45Ca2+ uptake inhibitions in rat DRG neuron. In particular, the amide 59 was identified as a potent antagonist with IC50 of 57 nM. The synthesis and structure-activity relationship of the diarylalkyl amides are also described.
- Li, Fu-Nan,Kim, Nam-Jung,Paek, Seung-Mann,Kwon, Do-Yeon,Min, Kyung Hoon,Jeong, Yeon-Su,Kim, Sun-Young,Park, Young-Ho,Kim, Hee-Doo,Park, Hyeung-Geun,Suh, Young-Ger
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experimental part
p. 3557 - 3567
(2009/09/27)
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- Diastereomeric salt resolution based synthesis of LY503430, an AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) potentiator
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This article describes the development and optimization of chemical reactions and subsequent preparation of the API LY503430 under cGMPs to fund first human dose (FHD) clinical evaluation as a potential therapeutic agent for Parkinson's disease. Reasons and rationale are presented for changes in solvents and reagents. One of the major developments presented here is the replacement of a chiral chromatography with a diastereomeric salt resolution. This article also discusses a preferred orientation issue with LY503430 which complicated the XRPD analysis.
- Magnus, Nicholas A.,Aikins, James A.,Cronin, Jason S.,Diseroad, William D.,Hargis, Amy D.,LeTourneau, Michael E.,Parker, Bruce E.,Reutzel-Edens, Susan M.,Schafer, John P.,Staszak, Michael A.,Stephenson, Gregory A.,Tameze, Shella L.,Zollars, Lisa M. H.
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p. 621 - 628
(2012/12/25)
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- Characterization of a series of 3-amino-2-phenylpropene derivatives as novel bovine chromaffin vesicular monoamine transporter inhibitors
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A series of 3-amino-2-phenylpropene (APP) derivatives have been synthesized and characterized as novel competitive inhibitors, with Ki values in the μM range, for the bovine chromaffin granule membrane monoamine transporter(s) (bVMAT). Although, these inhibitors are structurally similar to the bVMAT substrate tyramine, none of them were measurably transported into the granule. Structure - activity studies have revealed that, while the 3′- or 4′-OH groups on the aromatic ring enhance the inhibition potency, Me or OMe groups in these positions reduce the inhibition potency. Halogen substitution on the 4′-position of the aromatic ring causes gradual increase of the inhibition potency parallel to the electron donor ability of the halogen. Substituents on the NH2 as well as on the 3-position of the alkyl chain reduce the inhibition potency. Comparative structure - activity analyses of APP derivatives with tyramine and the neurotoxin 1-methyl-4-phenylpyridinium suggest that the flexibility of the side chain and the relative orientation of the NH2 group may be critical for the efficient transport of the substrate through the bVMAT. Comparable bVMAT affinities of these inhibitors to that of DA and other pharmacologically active amines suggest that they are suitable for the structure activity and mechanistic studies of monoamine transporters and may also be useful in modeling the mechanism of action of amphetamine-related derivatives.
- Perera, Rohan P.,Wimalasena, D. Shyamali,Wimalasena, Kandatege
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p. 2599 - 2605
(2007/10/03)
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- Antiarrhythmic agents. 2, 3, and 4 substituted benzylamines
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The synthesis of a series of 2, 3, and 4 substituted benzylamine derivatives is described. These compounds were studied for their effect on experimental cardiac arrhythmias. Many of the derivatives, but in particular 2 (p methoxyphenylethynyl) benzylamine
- Remy,van Saun Jr.,Engelhardt
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p. 142 - 148
(2007/10/06)
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