- In-situ facile synthesis novel N-doped thin graphene layer encapsulated Pd@N/C catalyst for semi-hydrogenation of alkynes
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Transition metal-catalyzed semi-hydrogenation of alkynes has become one of the most popular methods for alkene synthesis. Specifically, the noble metal Pd, Rh, and Ru-based heterogeneous catalysts have been widely studied and utilized in both academia and industry. But the supported noble metal catalysts are generally suffering from leaching or aggregation during harsh reaction conditions, which resulting low catalytic reactivity and stability. Herein, we reported the facile synthesis of nitrogen doped graphene encapsulated Pd catalyst and its application in the chemo-selective semi-hydrogenation of alkynes. The graphene layer served as “bulletproof” over the active Pd Nano metal species, which was confirmed by X-ray and TEM analysis, enhanced the catalytic stability during the reaction conditions. The optimized prepared Pd@N/C catalyst showed excellent efficiency in semi-hydrogenation of phenylacetylene and other types of alkynes with un-functionalized or functionalized substituents, including the hydrogenation sensitive functional groups (NO2, ester, and halogen).
- Liu, Jianguo,Lin, Shanshan,Sun, Jiangming,Ma, Longlong
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p. 553 - 560
(2021/12/03)
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- Regioselective Radical Arene Amination for the Concise Synthesis ofortho-Phenylenediamines
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The formation of arene C-N bonds directly from C-H bonds is of great importance and there has been rapid recent development of methods for achieving this through radical mechanisms, often involving reactiveN-centered radicals. A major challenge associated with these advances is that of regiocontrol, with mixtures of regioisomeric products obtained in most protocols, limiting broader utility. We have designed a system that utilizes attractive noncovalent interactions between an anionic substrate and an incoming radical cation in order to guide the latter to the areneorthoposition. The anionic substrate takes the form of a sulfamate-protected aniline and telescoped cleavage of the sulfamate group after amination leads directly toortho-phenylenediamines, key building blocks for a range of medicinally relevant diazoles. Our method can deliver both free amines and monoalkyl amines allowing access to unsymmetrical, selectively monoalkylated benzimidazoles and benzotriazoles. As well as providing concise access to valuableortho-phenylenediamines, this work demonstrates the potential for utilizing noncovalent interactions to control positional selectivity in radical reactions.
- Gillespie, James E.,Morrill, Charlotte,Phipps, Robert J.
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supporting information
p. 9355 - 9360
(2021/07/19)
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- Mo–Catalyzed One-Pot Synthesis of N-Polyheterocycles from Nitroarenes and Glycols with Recycling of the Waste Reduction Byproduct. Substituent-Tuned Photophysical Properties
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A catalytic domino reduction–imine formation–intramolecular cyclization–oxidation for the general synthesis of a wide variety of biologically relevant N-polyheterocycles, such as quinoxaline- and quinoline-fused derivatives, and phenanthridines, is reported. A simple, easily available, and environmentally friendly dioxomolybdenum(VI) complex has proven to be a highly efficient and versatile catalyst for transforming a broad range of starting nitroarenes involving several redox processes. Not only is this a sustainable, step-economical as well as air- and moisture-tolerant method, but also it is worth highlighting that the waste byproduct generated in the first step of the sequence is recycled and incorporated in the final target molecule, improving the overall synthetic efficiency. Moreover, selected indoloquinoxalines have been photophysically characterized in cyclohexane and toluene with exceptional fluorescence quantum yields above 0.7 for the alkyl derivatives.
- Hernández-Ruiz, Raquel,Rubio-Presa, Rubén,Suárez-Pantiga, Samuel,Pedrosa, María R.,Fernández-Rodríguez, Manuel A.,Tapia, M. José,Sanz, Roberto
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supporting information
p. 13613 - 13623
(2021/08/23)
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- Exploring the Potential of 2-(2-Nitrophenyl)ethyl-Caged N-Hydroxysulfonamides for the Photoactivated Release of Nitroxyl (HNO)
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The emergence of nitroxyl (HNO) as a biological signaling molecule is attracting increasing attention. HNO-based prodrugs show considerable potential in treating congestive heart failure, with HNO reacting rapidly with metal centers and protein-bound and free thiols. A new class of 2-(2-nitrophenyl)ethyl (2-NPE)-photocaged N-hydroxysulfonamides has been developed, and the mechanisms of photodecomposition have been investigated. Three photodecomposition pathways are observed: The desired concomitant C-O/N-S bond cleavage to generate HNO, sulfinate, and 2-nitrostyrene, C-O bond cleavage to give the parent sulfohydroxamic acid and 2-nitrostyrene, and O-N bond cleavage to release a sulfonamide and 2-nitrophenylacetaldehyde. Laser flash photolysis experiments provide support for a Norrish type II mechanism involving 1,5-hydrogen atom abstraction to generate an aci-nitro species. A mechanism is proposed in which the (Z)-aci-nitro intermediate undergoes either C-O bond cleavage to release RSO2NHO(H), concerted C-O/N-S bond cleavage to generate sulfinate and HNO, or isomerization to the (E)-isomer prior to O-N bond cleavage. The pKa of the N(H) of the N-hydroxysulfonamide plays a key role in determining whether C-O or concerted C-O/N-S bond cleavage occurs. Deprotonating this site favors the desired C-O/N-S bond cleavage at the expense of an increased level of undesired O-N bond cleavage. Triplet state quenchers have no effect on the observed photoproducts.
- Bharadwaj, Vinay,Brasch, Nicola E.,Rahman, Mohammad S.,Sampson, Paul,Seed, Alexander J.
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p. 16448 - 16463
(2021/12/06)
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- Cross-Coupling Reactions with 2-Amino-/Acetylamino-Substituted 3-Iodo-1,4-naphthoquinones: Convenient Synthesis of Novel Alkenyl- And Alkynylnaphthoquinones and Derivatives
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Functionalized 1,4-naphthoquinones have been employed as versatile synthons in organic synthesis, in addition to presenting a large array of biological activities. Herein, the applications of 2-amino-/ acetylamino-substituted 3-iodo-1,4-naphthoquinones in cross-coupling reactions are described to successfully afford sixteen novel 3-styryl-1,4-naphthoquinones (amino-stilbene-quinone hybrids) and four 3-alkynyl-1,4-naphthoquinone in overall good yields. Interestingly, the alkynylated derivatives could be obtained from ligand- and Pd-free Cu I -mediated cross-coupling reactions, after extensive investigations to exclude Pd as a co-catalyst. Lastly, the desilanized terminal alkyne was subjected to click chemistry reactions to give two novel triazole-1,4-naphthoquinone hybrids.
- Demidoff, Felipe C.,Rodrigues Filho, Eduardo José P.,De Souza, Andréa Luzia F.,Netto, Chaquip D.,De Carvalho, Leandro L.
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supporting information
p. 4097 - 4109
(2021/08/31)
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- Direct Arylation of Distal and Proximal C(sp3)-H Bonds of t-Amines with Aryl Diazonium Tetrafluoroborates via Photoredox Catalysis
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A visible light-mediated arylation protocol for t-amines has been reported through the coupling of γ- and α-amino alkyl radicals with different aryl diazonium salts using Ru(bpy)3Cl2·6H2O as a photocatalyst. Structurally different 9-aryl-9,10-dihydroacridine, 1-aryl tetrahydroisoquinoline, hexahydropyrrolo[2,1-a]isoquinoline, and hexahydro-2H-pyrido[2,1-a]isoquinoline frameworks with different substitution patterns have been synthesized in good yield using this methodology.
- Mondal, Pradip Kumar,Tiwari, Sandip Kumar,Singh, Pushpendra,Pandey, Ganesh
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p. 17184 - 17196
(2021/12/02)
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- Azepino-indazoles as calcitonin gene-related peptide (CGRP) receptor antagonists
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Calcitonin gene-related peptide (CGRP) receptor antagonists have been shown clinically to be effective treatments for migraine. Zavegepant (BHV-3500, BMS-742413) is a high affinity antagonist of the CGRP receptor (hCGRP Ki = 0.023 nM) that has
- Mercer, Stephen E.,Chaturvedula, Prasad V.,Conway, Charles M.,Cook, Deborah A.,Davis, Carl D.,Pin, Sokhom S.,Macci, Robert,Schartman, Richard,Signor, Laura J.,Widmann, Kimberly A.,Whiterock, Valerie J.,Chen, Ping,Xu, Cen,Herbst, John J.,Kostich, Walter A.,Thalody, George,Macor, John E.,Dubowchik, Gene M.
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supporting information
(2020/12/17)
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- Precise molecular design for BN-modified polycyclic aromatic hydrocarbons toward mechanochromic materials
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The development of smart materials, in particular those exhibiting highly sensitive mechanochromic luminescence (MCL) is desirable, but challenging since the MCL internal mechanism and the structure-performance relationship still remain unclear. Herein, w
- Cao, Dapeng,Cao, Xiaohua,Han, Chuan,Hu, Huanan,Huang, Huanan,Liu, Guochang,Peng, You,Wang, Yawei,Xu, Zhixiong,Yan, Ping,Zhan, Changchao,Zhou, Ying
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p. 22023 - 22031
(2020/11/11)
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- Hypercoordinated diorganoantimony(III) compounds of types [2-(Me2NCH2)C6H4]2SbL and [PhCH2N(CH2C6H4)2]SbL (L = Cl, ONO2, OSO2CF3). Synthesis, structure and catalytic behaviour in the Henry reaction
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The compounds [2-(Me2NCH2)C6H4]2SbL (L = ONO2 (2), OSO2CF3 (3)) and [PhCH2N(CH2C6H4)2]SbL (L = ONO2 (5), OSO2CF3 (6)) were prepared by reacting [2-(Me2NCH2)C6H4]2SbCl (1) and [PhCH2N(CH2C6H4)2]SbCl (4), respectively, with the appropriate silver(I) salt in a 1:1 molar ratio. The new species 2–6 were structurally characterized in solution using multinuclear NMR and in the solid state using infrared spectroscopy. The solid-state structures for compounds 2, 4 and 6, as well as for the hydrolysis ionic product [{2-(Me2N+HCH2)C6H4}{2-(Me2NCH2)C6H4}SbOH][CF3SO3]? (3h) were determined using single-crystal X-ray diffraction. Medium to strong intramolecular N→ Sb interactions were observed in all these four compounds, thus resulting in hypercoordinated organoantimony(III) species 14-Sb-6 in 2 and 10-Sb-4 in the cation of 3h and in 4 and 6. Compounds 1–6 and the starting amines PhCH2NMe2 and PhCH2N(CH2C6H4Br-2)2 were investigated as catalysts in the Henry (nitroaldol) addition of nitromethane to benzaldehyde. The activity of compounds 1–6 resulted as an effect of the cooperation of the positively charged antimony with the negatively charged nitrogen.
- ?uteu, R?zvan,Candu, Natalia,Parvulescu, Vasile I.,Ra?, Ciprian I.,Simion, Andrada,Sivestru, Anca,Sivestru, Cristian
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- Hydroxyl Assisted Rhodium Catalyst Supported on Goethite Nanoflower for Chemoselective Catalytic Transfer Hydrogenation of Fully Converted Nitrostyrenes
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Control of chemoselectivity is a special challenge for the reduction of nitroarenes bearing one or more unsaturated groups. Here, we report a flower-like Rh/α-FeOOH catalyst for the chemoselective hydrogenation of nitrostyrene to vinylaniline over full conversion, which benefits the new functionalized aminostyrene because the multisubstituted aminostyrenes are usually commercially unavailable. This catalyst does not only show desirable selectivity for the vinylanilines, but also exhibits the inertness to various other reducible groups over wide reaction duration. The catalytic selectivity for the reduction of the nitro group towards vinyl group was investigated by the control experiments and FT-IR analysis. We have found that the abundant hydroxyl groups in the α-FeOOH may contribute to the improvement of catalytic activity and selectivity. Furthermore, the catalyst exhibits excellent stability and keeps its catalytic performance even after 6 cycles. (Figure presented.).
- Hu, Zenan,Ai, Yongjian,Liu, Lei,Zhou, Junjie,Zhang, Gang,Liu, Hongqi,Liu, Xiangyu,Liu, Zhibo,Hu, Jianshe,Sun, Hong-bin,Liang, Qionglin
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supporting information
p. 3146 - 3154
(2019/05/10)
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- A cascade approach to 3D cyclic carbamates: Via an ionic decarboxylative functionalization of olefinic oxamic acids
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An m-CPBA-mediated intramolecular epoxidation-decarboxylative alkoxylation cascade reaction of olefinic oxamic acids has been developed. The distinct ionic decarboxylative mechanism was preliminarily revealed. The protocol features mild reaction conditions and operational simplicity, allowing the construction of diverse medicinally valuable 5-7 membered 3D cyclic carbamate architectures in moderate to high yields.
- Fan, Huaqiang,Wan, Yi,Pan, Peng,Cai, Wenbin,Liu, Shihui,Liu, Chuanxu,Zhang, Yongqiang
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supporting information
p. 86 - 89
(2019/12/25)
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- Synthesis of functionalized helical BN-benzo[c] phenanthrenes
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A novel parent BN-benzo[c]phenanthrene, with helical chirality and remarkable structural features, has been easily obtained in three steps with a global yield of 55%. Moreover, Cl-substituted derivatives have been prepared and these have served as useful starting materials for the development of palladium-catalyzed cross-coupling reactions.
- Abengózar, Alberto,García-García, Patricia,Sucunza, David,Pérez-Redondo, Adrián,Vaquero, Juan J.
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supporting information
p. 2467 - 2470
(2018/03/21)
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- Enantioselective, Catalytic Vicinal Difluorination of Alkenes
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The enantioselective, catalytic vicinal difluorination of alkenes is reported by II/IIII catalysis using a novel, C2-symmetric resorcinol derivative. Catalyst turnover via in situ generation of an ArIIIIF2 species is enabled by Selectfluor oxidation and addition of an inexpensive HF–amine complex. The HF:amine ratio employed in this process provides a handle for regioselective orthogonality as a function of Br?nsted acidity. Selectivity reversal from the 1,1-difluorination pathway (geminal) to the desired 1,2-difluorination (vicinal) is disclosed (>20:1 in both directions). Validation with electron deficient styrenes facilitates generation of chiral bioisosteres of the venerable CF3 unit that is pervasive in drug discovery (20 examples, up to 94:06 e.r.). An achiral variant of the reaction is also presented using p-TolI (up to >95 % yield).
- Scheidt, Felix,Sch?fer, Michael,Sarie, Jér?me C.,Daniliuc, Constantin G.,Molloy, John J.,Gilmour, Ryan
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supporting information
p. 16431 - 16435
(2018/11/23)
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- Water-Soluble Hypervalent Iodine(III) Having an I-N Bond. A Reagent for the Synthesis of Indoles
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A readily accessible and bench-stable water-soluble hypervalent iodine(III) reagent (phenyliodonio)sulfamate (PISA) with an I-N bond was synthesized, and its structure was characterized by X-ray crystallography. With PISA, various indoles were synthesized via C-H amination of 2-alkenylanilines involving an aryl migration/intramolecular cyclization cascade with excellent regioselectivity in aqueous CH3CN. Notably, using this new method as the key step, not only two drug molecules, indometacin and zidometacin, but also another bioactive molecule, pravadoline, were synthesized.
- Xia, Hai-Dong,Zhang, Yan-Dong,Wang, Yan-Hui,Zhang, Chi
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supporting information
p. 4052 - 4056
(2018/07/15)
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- A [...] reagent catalytic synthesis method and its application (by machine translation)
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The invention provides a method for catalytic synthesis of [...] reagent method and its application, the [...] reagent of formula (1) as shown in the structure of the organic solution: Its catalytic synthesis method is: under protection of inert gas, (II) shown [...] catalyst copper complex and active zinc powder added to the organic solvent, under a certain temperature [...] methyl bromide, then temperature reaction until the zinc powder the reaction is complete, the obtained white suspension is [...] reagent. (II), the invention compared with the prior art, the major advantage of: provides a [...] reagent catalytic synthesis method, is formed from a copper compound as a catalyst in the synthesis of the reagent [...] effect, and in the carbonyl of methylene compounds have been obtained in the application. (by machine translation)
- -
-
Paragraph 0039; 0040;0043; 0044; 0046
(2018/04/28)
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- Terminal Alkenes from Acrylic Acid Derivatives via Non-Oxidative Enzymatic Decarboxylation by Ferulic Acid Decarboxylases
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Fungal ferulic acid decarboxylases (FDCs) belong to the UbiD-family of enzymes and catalyse the reversible (de)carboxylation of cinnamic acid derivatives through the use of a prenylated flavin cofactor. The latter is synthesised by the flavin prenyltransferase UbiX. Herein, we demonstrate the applicability of FDC/UbiX expressing cells for both isolated enzyme and whole-cell biocatalysis. FDCs exhibit high activity with total turnover numbers (TTN) of up to 55000 and turnover frequency (TOF) of up to 370 min?1. Co-solvent compatibility studies revealed FDC's tolerance to some organic solvents up 20 % v/v. Using the in-vitro (de)carboxylase activity of holo-FDC as well as whole-cell biocatalysts, we performed a substrate profiling study of three FDCs, providing insights into structural determinants of activity. FDCs display broad substrate tolerance towards a wide range of acrylic acid derivatives bearing (hetero)cyclic or olefinic substituents at C3 affording conversions of up to >99 %. The synthetic utility of FDCs was demonstrated by a preparative-scale decarboxylation.
- Aleku, Godwin A.,Prause, Christoph,Bradshaw-Allen, Ruth T.,Plasch, Katharina,Glueck, Silvia M.,Bailey, Samuel S.,Payne, Karl A. P.,Parker, David A.,Faber, Kurt,Leys, David
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p. 3736 - 3745
(2018/08/03)
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- An Easy-to-Machine Electrochemical Flow Microreactor: Efficient Synthesis of Isoindolinone and Flow Functionalization
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Flow electrochemistry is an efficient methodology to generate radical intermediates. An electrochemical flow microreactor has been designed and manufactured to improve the efficiency of electrochemical flow reactions. With this device only little or no supporting electrolytes are needed, making processes less costly and enabling easier purification. This is demonstrated by the facile synthesis of amidyl radicals used in intramolecular hydroaminations to produce isoindolinones. The combination with inline mass spectrometry facilitates a much easier combination of chemical steps in a single flow process.
- Folgueiras-Amador, Ana A.,Philipps, Kai,Guilbaud, Sébastien,Poelakker, Jarno,Wirth, Thomas
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supporting information
p. 15446 - 15450
(2017/11/10)
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- NH2-directed C-H alkenylation of 2-vinylanilines with vinylbenziodoxolones
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The first directing-group-mediated C-H alkenylation with alkenyl-λ3-iodanes as electrophilic alkene-transfer reagents has been developed. The application of free aromatic amines as challenging but synthetically valuable directing groups in combination with an IrIII catalyst enabled the synthesis of highly desirable 1, 3- dienes in excellent yields of up to 98% with high to perfect (Z, E) stereoselectivity. A broad substrate scope and further synthetic modifications are demonstrated.
- Boelke, Andreas,Caspers, Lucien D.,Nachtsheim, Boris J.
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supporting information
p. 5344 - 5347
(2017/11/07)
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- Synthesis of Stilbene-Quinone Hybrids through Heck Reactions in PEG-400
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Styrenes were coupled with 3-iodolawsone in PEG-400 at 90 °C, leading stereoselectively to (E)-stilbene-quinone hybrids through Heck reactions. The best reaction conditions were found to be the use of NaOH (3 equiv) and 10 mol% of palladium acetate at 90 °C for 15 minutes. The chemical yields of the Heck reactions using styrenes with electron-withdrawing groups (65-98%) were greater than styrenes bearing electron-donating groups (7-32%) on the aromatic ring. In particular, the chemical yields of Heck reactions involving nitrostyrenes were the best ones observed.
- Demidoff, Felipe C.,De Souza, Fabrícia P.,Netto, Chaquip D.
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supporting information
p. 5217 - 5223
(2017/11/28)
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- Synthesis of carbazole analogs via Grob fragmentation of norbornyl α-diketones
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A regioselective synthesis of carbazole analogs belonging to both the categories of natural origin, viz., microorganisms and higher plant source is reported. The synthesis of carbazole derivatives possessing a methylester group at C-1 position has been ac
- Sravanthi, Kadavergu,Agrawal, Sumit Kumar,Rao, Chintada Nageswara,Khan, Faiz Ahmed
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supporting information
p. 3449 - 3452
(2016/07/18)
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- SQUALENE COMPOUNDS AS MODULATORS OF LDL-RECEPTOR EXPRESSION
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The present invention relates to compounds that modify low density lipoprotein receptor (LDLR) expression. The compounds have the structural formula I shown below: wherein m, R1, n, R2 and R3 are each as defined herein. The present invention also relates to processes for the preparation of these compounds, to pharmaceutical compositions comprising them, and to their use in the treatment of diseases or disorders associated with elevated levels of low density lipoprotein cholesterol (LDL-C).
- -
-
Paragraph 0005; 0024
(2016/04/20)
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- Copper-catalyzed trifluoromethylation of alkenes: Synthesis of trifluoromethylated benzoxazines
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A simple base and ligand free copper catalyzed method for the construction of trifluoromethylated benzoxazines has been developed by using Umemoto's reagent. It involves the oxidative difunctionalization of alkenes through tandem C-O and C-CF3 bond formations. Furthermore, synthesized benzoxazines were selectively converted into trifluoromethylated allylic and (E)-vinylic benzamides by the treatment of KOtBu and CH3Li, respectively.
- Jana, Sadhan,Ashokan, Athira,Kumar, Shailesh,Verma, Ajay,Kumar, Sangit
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supporting information
p. 8411 - 8415
(2015/08/06)
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- Vinylic MIDA boronates: New building blocks for the synthesis of aza-heterocycles
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Abstract A two-step synthesis of structurally diverse pyrrole-containing bicyclic systems is reported. ortho-Nitro-haloarenes coupled with vinylic N-methyliminodiacetic acid (MIDA) boronates generate ortho-vinyl-nitroarenes, which undergo a "metal-free" nitrene insertion, resulting in a new pyrrole ring. This novel synthetic approach has a wide substrate tolerance and it is applicable in the preparation of more complex "drug-like" molecules. Interestingly, an ortho-nitro-allylarene derivative furnished a cyclic β-aminophosphonate motif. Old dog, new tricks: A two-step synthesis of structurally diverse pyrrole-containing bicyclic systems is reported. ortho-Nitro-haloarenes coupled with vinylic N-methyliminodiacetic acid (MIDA) boronates generate ortho-vinyl-nitroarenes, which undergo a "metal-free" nitrene insertion, resulting in a new pyrrole ring. This approach has a wide substrate tolerance and it is applicable in the preparation of more complex "drug-like" molecules. Interestingly, an ortho-nitro-allylarene derivative furnished a cyclic β-aminophosphonate motif.
- Llona-Minguez, Sabin,Desroses, Matthieu,Ghassemian, Artin,Jacques, Sylvain A.,Eriksson, Lars,Isacksson, Rebecka,Koolmeister, Tobias,Stenmark, P?l,Scobie, Martin,Helleday, Thomas
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supporting information
p. 7394 - 7398
(2015/05/13)
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- Polyaniline-anchored palladium catalyst-mediated Mizoroki-Heck and Suzuki-Miyauraa reactions and one-pot Wittig-Heck and Wittig-Suzuki reactions
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A polyaniline-anchored palladium catalyst was prepared and screened for coupling reactions of aryl halides. The robust and recyclable catalyst was effective in Mizoroki-Heck and Suzuki-Miyaura reactions of aryl bromides and aryl iodides. The catalyst system was further employed for one-pot Wittig-Heck and Wittig-Suzuki combinations to build conjugated compounds in good conversions.
- Patel, Heta A.,Patel, Arun L.,Bedekar, Ashutosh V.
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- In Situ Generation of Formaldehyde and Triphenylphosphine from (Hydroxymethyl)triphenylphosphonium and Its Application in Wittig Olefination
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The reaction of (hydroxymethyl)triphenylphosphonium with benzylic or allylic halide under basic conditions at room temperature affords terminal alkenes in 61-89% yields. In this reaction, both formaldehyde and triphenylphosphine are in situ generated from (hydroxymethyl)triphenylphosphonium and further undergo Wittig olefination with benzylic or allylic halide.
- Huang, Wenhua,Xu, Jie
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supporting information
p. 1777 - 1782
(2015/08/06)
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- Indole synthesis based on a modified koser reagent
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A new metal-free method for the rapid and productive preparation of indoles has been developed. This process is based on sterically congested hypervalent iodine compounds of the family of Koser reagents, and iodosobenzene in combination with 2,4,5-tris-isopropylbenzene sulfonic acid provides the highest yields and fastest reaction times. This reagent alone promotes the chemoselective oxidative cyclization of 2-amino styrenes to indoles in high yields under mild conditions. Convenient route to indole: A fast, productive, and operationally simple indole synthesis was developed.
- Fra, Laura,Millán, Alba,Souto, José A.,Mu?iz, Kilian
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supporting information
p. 7349 - 7353
(2014/07/21)
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- Efficient cyclization of tertiary amines and alkenes promoted by KOt-Bu-DMF
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Nitrogen heterocycles could be prepared in good yields via intramolecular cyclization of tertiary amines and alkenes promoted by KOt-Bu-DMF. This journal is The Royal Society of Chemistry 2013.
- Chen, Yan-Yan,Zhang, Xue-Jing,Yuan, Hui-Min,Wei, Wen-Tao,Yan, Ming
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supporting information
p. 10974 - 10976
(2013/11/19)
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- One-pot ring-closing metathesis/1,3-dipolar cycloaddition through assisted tandem ruthenium catalysis: Synthesis of a dye with isoindolo[2,1-a]quinoline structure
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The one-pot tandem reaction of N-alkyl-N-allyl-2-vinylaniline derivatives with benzo- or naphthoquinones and a ruthenium-alkylidene catalyst leads to isoindolo[2,1-a]quinolines in a variety of colors, which can be altered by exchanging the substituent on the core heterocycle (see scheme). This reaction offers a new synthetic method for π-conjugated small molecules from simple aniline derivatives. Copyright
- Arisawa, Mitsuhiro,Fujii, Yuki,Kato, Hiroshige,Fukuda, Hayato,Matsumoto, Takashi,Ito, Mika,Abe, Hiroshi,Ito, Yoshihiro,Shuto, Satoshi
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supporting information
p. 1003 - 1007
(2013/03/13)
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- A new photoclick reaction strategy: Photo-induced catalysis of the thiol-Michael addition via a caged primary amine
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The utilization of 2-(2-nitrophenyl)propyloxycarbonyl (NPPOC) as a photolabile primary amine cage enables the thiol-Michael 'click' reaction to be photo-triggered. The photolabile amine exhibits efficient catalytic activity upon UV irradiation and is shown to initiate the photopolymerization of tetrathiol and diacrylate comonomers via Michael addition.
- Xi, Weixian,Krieger, Matthias,Kloxin, Christopher J.,Bowman, Christopher N.
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supporting information
p. 4504 - 4506
(2013/06/05)
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- Decarboxylative cross-coupling of mesylates catalyzed by copper/palladium systems with customized imidazolyl phosphine ligands
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The activation of the inert C-O bonds in mesylates through the use of a new class of imidazolyl phosphines allows the decarboxylative coupling of aryl mesylates as well as polysubstituted alkenyl mesylates. Variation of the ligands leads to two complementary methods providing the corresponding biaryls and polysubstituted olefins in good yields. Copyright
- Song, Bingrui,Knauber, Thomas,Goo?en, Lukas J.
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p. 2954 - 2958
(2013/04/11)
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- Metal-ligand core-shell nanocomposite catalysts for the selective semihydrogenation of alkynes
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Catalysts with a sheltered upbringing: Novel core-shell nanocomposite catalysts consisting of active metal nanoparticles encapsulated by macroligands have been prepared. They have Pd nanoparticles (PdNPs) as an active core and shell ligands having sulfoxide moieties coordinated to the PdNPs. The shell protects the catalyst from coordination by alkenes and allows the lead-free selective semihydrogenation of a wide range of alkynes without any additives (see scheme). Copyright
- Mitsudome, Takato,Takahashi, Yusuke,Ichikawa, Satoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 1481 - 1485
(2013/04/10)
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- Oxidative alkoxycarbonylation of terminal alkenes with carbazates
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A range of terminal alkenes smoothly underwent palladium-catalyzed oxidative alkoxycarbonylation with carbazates under an oxygen atmosphere to afford structurally diverse α,β-unsaturated esters in moderate to good yields with excellent regioselectivity and E selectivity.
- Su, Yu-Han,Wu, Zhao,Tian, Shi-Kai
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supporting information
p. 6528 - 6530
(2013/07/26)
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- A general and efficient aldehyde decarbonylation reaction by using a palladium catalyst
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A facile decarbonylation reaction of aldehydes has been developed by employing Pd(OAc)2. A wide variety of substrates are decarbonylated, without using any exogenous ligand for palladium as well as CO-scavenger.
- Modak, Atanu,Deb, Arghya,Patra, Tuhin,Rana, Sujoy,Maity, Soham,Maiti, Debabrata
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supporting information; experimental part
p. 4253 - 4255
(2012/05/04)
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- Concise total syntheses of Marinoquinolines A-C
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The first concise total syntheses of pyrroloquinoline natural products, Marinoquinolines A-C, have been achieved in six linear steps from commercially available starting materials. The key steps were a reaction between (p-tolylsulfonyl)methylisocyanide (TosMIC) and α, β-unsaturated ester under basic condition to prepare the pyrrole moiety and Morgen-Walls reaction to construct quinoline ring.
- Ni, Lijun,Li, Ziyuan,Wu, Fan,Xu, Jinyi,Wu, Xiaoming,Kong, Lingyi,Yao, Hequan
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scheme or table
p. 1271 - 1274
(2012/03/27)
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- Highly efficient Pd/SiO2-dimethyl sulfoxide catalyst system for selective semihydrogenation of alkynes
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Silica-supported Pd nanoparticles (Pd/SiO2) with dimethyl sulfoxide (DMSO) show excellent catalytic activity and selectivity for the semihydrogenation of alkynes. Small amounts of DMSO drastically suppress the overhydrogenation and isomerization of alkenes. This catalyst system is also applicable to both internal and terminal alkynes. Furthermore, the Pd/SiO 2 catalyst was separable from the reaction mixture after the hydrogenation and reusable without loss of its high catalytic activity or selectivity.
- Takahashi, Yusuke,Hashimoto, Norifumi,Hara, Takayoshi,Shimazu, Shogo,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 405 - 407
(2012/10/29)
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- Reduction of 1-(2-Chloroethyl)-2-nitrobenzene and 1-(2-Bromoethyl)-2- nitrobenzene at carbon cathodes: Electrosynthetic routes to 1-nitro-2- vinylbenzene and 1H -indole
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Studies of the electrochemical reductions of 1-(2-chloroethyl)-2- nitrobenzene (1) and 1-(2-bromoethyl)-2-nitrobenzene (2) at carbon cathodes in dimethylformamide (DMF) containing tetramethylammonium tetrafluoroborate (TMABF4) have been undertaken. Cyclic voltammograms for 1 and 2 exhibit three irreversible cathodic peaks, the first of which is attributed to one-electron reduction of the nitro group, and the resulting nitro radical-anion immediately reacts as a base with the adjacent alkyl halide moiety via an E2 elimination to produce 1-nitro-2-vinylbenzene. At a potential corresponding to the first cathodic peak, bulk electrolyses of 1 or 2 in the absence of a proton donor afford 1-nitro-2-vinylbenzene as principal product, along with 1H -indole and a dimeric species. However, when 1 or 2 is electrolyzed in the presence of either phenol or 2,4-pentanedione as a proton source, the only significant product is 1H -indole. A mechanistic picture for the reductions of 1 and 2 is proposed, and a separate examination of the electrochemical behavior of 1-nitro-2-vinylbenzene has been included as part of this work.
- Du, Peng,Peters, Dennis G.
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experimental part
p. F167-F172
(2010/11/21)
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- Palladium on charcoal-catalyzed ligand-free Stille coupling
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An efficient ligand-free Stille coupling reaction catalyzed by palladium on charcoal was developed. Tetraphenyltin was reacted with a variety of aryl halides including aryl chlorides using LiCl as an additive. The reactions of tributyl organotin compounds with aryl iodides were effectively expedited by the addition of LiF. These reactions efficiently proceeded without a phosphine or arsenic ligand and no leached palladium was detected in the reaction mixture.
- Yabe, Yuki,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
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experimental part
p. 8654 - 8660
(2010/11/19)
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- Highly selective and potent μ opioid ligands by unexpected substituent on morphine skeleton
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Unexpected substituent on the well-known morphine skeleton is described to be account for highly selective and potent μ opioid ligands, which is strongly connected to substituted aromatic groups on this omitted 8α-position.
- Li, Wei,Tao, Yi-Min,Tang, Yun,Xu, Xue-Jun,Chen, Jie,Fu, Wei,Wang, Xing-Hai,Chao, Bo,Sheng, Wei,Xie, Qiong,Qiu, Zhui-Bai,Liu, Jing-Gen
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supporting information; body text
p. 418 - 421
(2010/03/25)
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- One-pot Suzuki/Heck sequence for the synthesis of (E)-stilbenes featuring a recyclable silica-supported palladium catalyst via a multi-component reaction in 1,3-propanediol
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The synthesis of (E)-stilbenes was performed following a one-pot Suzuki/Heck sequence through the use of potassium vinyltrifluoroborate. The combination of heterogeneous palladium/silica (Pd/SiO2) catalyst with potassium phosphate monohydrate (K3PO4?H 2O) as base resulted in useful to good isolated yields regardless of the ortho-, meta- or para-substitution of the aryl halides employed. In a sustainable approach, we found that bio-sourced 1,3- propanediol could advantageously replace N-methylpyrrolidone (NMP) as similar yields were obtained. Moreover, the reactivity gap between aryl iodides and bromides resulting from the use of 1,3-propanediol allowed an efficient multi-component approach toward the synthesis of (E)-stilbenes. Furthermore, this heterogeneous catalyst was found to be extremely robust despite the use of aerobic conditions and was successfully re-used over several cycles.
- Joucla, Lionel,Cusati, Giuseppe,Pinel, Catherine,Djakovitch, Laurent
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scheme or table
p. 1993 - 2001
(2010/10/20)
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- Efficient heterogeneous vinylation of aryl halides using potassium vinyltrifluoroborate
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An efficient heterogeneously palladium catalysed procedure for the vinylation of aryl iodides and bromides is reported. Using common reaction conditions (Pd/C 2 mol %, AcONa·3H2O, NMP or NMP/H2O), good to complete conversions (40-100%) with high selectivities (79-100%) towards the expected vinylaromatic were achieved.
- Joucla, Lionel,Cusati, Giuseppe,Pinel, Catherine,Djakovitch, Laurent
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p. 4738 - 4741
(2008/12/21)
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- Copper-carbene complexes as catalysts in the synthesis of functionalized styrenes and aliphatic alkenes
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(NHC)-Cu (NHC = N-heterocyclic carbene) complexes efficiently catalyzed the methylenation of a variety of aliphatic and aromatic aldehydes and ketones in the presence of trimethylsilyldiazomethane, triphenylphosphine, and 2-propanol. The copper catalysts are not only inexpensive compared to rhodium complexes, but they also exhibit better functional group compatibility with aromatic aldehydes and ketones. Indeed very high yields were obtained for the formation of styrenes containing nitro, trifluoromethyl, amino, and ester groups, as well as for pyridine-, pyrrole-, and indole-substituted alkenes.
- Lebel, Helene,Davi, Michael,Diez-Gonzalez, Silvia,Nolan, Steven P.
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p. 144 - 149
(2007/10/03)
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- Enantioconvergent hydrolysis of styrene epoxides by newly discovered epoxide hydrolases in mung bean
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Two novel epoxide hydrolases were discovered in mung bean (Phaseolus radiatus L.) for the first time, either of which can catalyze enantioconvergent hydrolysis of styrene epoxides. Their regioselectivity coefficients are more than 90% for the p-nitrostyrene oxide. Furthermore, the crude mung bean powder was also shown to be a cheap and practical biocatalyst, allowing a one-step asymmetric synthesis of chiral (R)-diols from racemic epoxides, in up to >99% ee and 68.7% overall yield (after recrystallization).
- Xu, Wei,Xu, Jian-He,Pan, Jiang,Gu, Qing,Wu, Xin-Yan
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p. 1737 - 1740
(2007/10/03)
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- Vinylation of aryl bromides using an inexpensive vinylpolysiloxane
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(Chemical Equation Presented) A mild and general method for the palladium-catalyzed vinylation of aryl bromides has been developed. The use of tetrabutylammonium fluoride (TBAF) as the activator and an inexpensive and nontoxic vinyl donor, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D4V, 1), allows for a general and high-yielding preparation of substituted styrenes.
- Denmark, Scott E.,Butler, Christopher R.
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- Total synthesis of (+)-(S)-angustureine and the determination of the absolute configuration of the natural product angustureine
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Angustureine, isolated from the bark of Galipea officinalis Hancock, is a novel quinoline alkaloid with a n-pentyl side chain at the 2-position. The total synthesis of (+)-(S)-angustureine and a determination of the absolute configuration of the natural p
- Theeraladanon, Chumpol,Arisawa, Mitsuhiro,Nakagawa, Masako,Nishida, Atsushi
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p. 827 - 831
(2007/10/03)
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- Generation of substituted styrenes via Suzuki cross-coupling of aryl halides with 2,4,6-trivinylcyclotriboroxane
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The synthesis of functionalized styrene derivatives can be readily achieved utilizing a Suzuki cross-coupling protocol between aryl halides and 2,4,6-trivinylcyclotriboroxane-pyridine complex. The scope and limitations of the procedure were demonstrated by investigation of an array of ortho-substituted aryl halides.
- Kerins, Fergal,O'Shea, Donal F.
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p. 4968 - 4971
(2007/10/03)
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- Pinacolboratamethyl-enetriphenylphosphonium iodide, a new methylene transfer reagent
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The title compound is easily prepared and reacts with various aldehydes and ketone. The reagent is compatible with free hydroxy groups. Yields with various aldehydes and ketones are in 50- > 99% range. Both aliphatic, aromatic and unsaturated carbonyls react.
- Al-Aziz Quntar, Abed,Srebnik, Morris
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p. 2575 - 2579
(2007/10/03)
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- Intramolecular 1,3-dipolar cycloaddition strategy for enantioselective synthesis of FR-900482 analogues
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(Equation presented) Enantioselective synthesis of FR-900482 analogues is described. The key reaction of the synthesis is intramolecular 1,3-dipolar cycloaddition of a highly functionalized nitrile oxide with complete stereo-and regioselectivities to construct the eight-membered benzazocine ring.
- Kambe, Mika,Arai, Eri,Suzuki, Masashi,Tokuyama, Hidetoshi,Fukuyama, Tohru
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p. 2575 - 2578
(2007/10/03)
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- Stereoselective process for producing nitro compounds
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The present invention relates to producing stereoselective nitro compounds by reacting a dicarbonyl compound with a nitrostyrene compound in the presence of a catalyst complex and a base.
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- 1-methyl-1-vinyl- and 1-methyl-1-(prop-2-enyl)silacyclobutane: Reagents for palladium-catalyzed cross-coupling reactions of aryl halides
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1-Methyl-1-vinylsilacyclobutane (1) and 1-methyl-1(prop-2- enyl)silacyclobutane (2) undergo rapid and high yielding cross-coupling with aromatic halides. Many different substituents and patterns on the aromatic moiety are tolerated. All reactions can be r
- Denmark, Scott E.,Wang, Zhigang
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p. 999 - 1003
(2007/10/03)
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- Synthesis of triphenylarsonium [11C]methylide, a new 11C-precursor. Application in the preparation of [2-11C]indole
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The synthesis of the new and highly reactive 11C-precursor triphenylarsonium [11C]methylide 1 and its conversion into [2-11C]indole 6 is described. [11C]Methyltriphenylarsonium iodide 4 was prepared by quaterniz
- Zessin,Steinbach,Johannsen
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p. 725 - 736
(2007/10/03)
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