- Synthesis of Functionalized Silsesquioxane Nanomaterials by Rhodium-Catalyzed Carbene Insertion into Si?H Bonds
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We report carbene insertion into Si?H bonds of polyhedral oligomeric silsesquioxanes (POSS) for the synthesis of highly functionalized siloxane nanomaterials. Dirhodium(II) carboxylates catalyze insertion of aryl-diazoacetates as carbene precursors to afford POSS structures containing both ester and aryl groups as orthogonal functional handles for further derivatization of POSS materials. Four diverse and structurally varied silsesquioxane core scaffolds with one, three, or eight Si?H bonds were evaluated with diazo reactants to produce a total of 20 new POSS compounds. Novel diazo compounds containing a fluorinated octyl group and boron-dipyrromethene (BODIPY) chromophore demonstrate the use of highly functionalized substrates. Transformations of aryl(ester)-functionalized POSS compounds derived from this method are demonstrated, including ester hydrolysis and Suzuki–Miyaura cross-coupling.
- Franz, Annaliese K.,Jagannathan, Jake R.,Targos, Karina
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supporting information
(2021/11/27)
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- B(C6F5)3-catalyzed O-H insertion reactions of diazoalkanes with phosphinic acids
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A highly efficient base-, metal-, and oxidant-free catalytic O-H insertion reaction of diazoalkanes and phosphinic acids in the presence of B(C6F5)3has been developed. This powerful methodology provides a green approach towards the synthesis of a broad spectrum of α-phosphoryloxy carbonyl compounds with good to excellent yields (up to 99% yield). The protocol features the advantages of operational simplicity, high atom economy, practicality, easy scalability and environmental friendliness.
- Jiang, Jun,Zhang, Xinzhi,Zhang, Yangyang,Zhao, Jincheng
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p. 5772 - 5776
(2021/07/12)
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- B(C6F5)3-Catalyzed site-selective N1-alkylation of benzotriazoles with diazoalkanes
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Alkylation of benzotriazoles is synthetically challenging, often leading to mixtures of N1 and N2 alkylation. Herein, metal-free catalytic site-selective N1-alkylation of benzotriazoles with diazoalkanes is described in the presence of 10 mol% of B(C6F5)3. These reactions provide N1-alkylated benzotriazoles in good to excellent yields and this protocol is successfully adapted to gram-scale syntheses as well as a derivative with antimicrobial activity.
- Guo, Jing,Mandal, Dipendu,Stephan, Douglas W.,Wu, Yile,Zhao, Yunbo
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p. 7758 - 7761
(2021/08/13)
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- Borane catalysed cyclopropenation of arylacetylenes
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Triarylboranes have gained substantial attention as catalysts for C-C bond forming reactions due to their remarkable catalytic activities. Herein, we report B(C6F5)3catalysed cyclopropenation of a wide variety of arylacetylenes using donor-acceptor diazoesters. A mild reaction protocol has been developed for the synthesis of functionalised cyclopropenes (33 examples) in good to excellent yields.
- Dasgupta, Ayan,Heard, Matthew J.,Melen, Rebecca L.,Stefkova, Katarina
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supporting information
p. 6736 - 6739
(2021/07/13)
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- Catalyst-free, scalable heterocyclic flow photocyclopropanation
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Industrial process development is driven by several factors, including safety, cost, robustness and environmental aspects. However, attempts to establish aryl diazo esters-which are highly valued in academic research for their reactivity as carbene precur
- Kl?pfer, Viktor,Eckl, Robert,Flo?, Johannes,Roth, Philippe M. C.,Reiser, Oliver,Barham, Joshua P.
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supporting information
p. 6366 - 6372
(2021/09/10)
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- Borane Catalyzed Selective Diazo Cross-Coupling Towards Pyrazoles
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Decomposition of donor-acceptor diazo compounds leads to the formation of reactive carbene intermediates. These can undergo a wide variety of carbene transfer reactions to yield synthetically useful products. Herein, we report a selective borane catalyzed cyclization reaction from the combination of two different diazo compounds to afford N-substituted pyrazoles. The selective decomposition of the more reactive α-aryl α-diazoester and subsequent reaction with a vinyl diazoacetate produces N-alkylated pyrazoles in a regioselective manner. Catalytic amounts of tris(pentafluorophenyl)borane (10 mol%) were employed to afford the pyrazole products (36 examples) in yields from 59 to 80%. Extensive DFT studies have been undertaken to interpret the mechanism for this reaction which was found to go through two tandem catalytic cycles, both catalyzed by B(C6F5)3.
- Ariafard, Alireza,Babaahmadi, Rasool,Dasgupta, Ayan,Gierlichs, Lukas,Melen, Rebecca L.,Pahar, Sanjukta,Yates, Brian F.
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- Azide Radical Initiated Ring Opening of Cyclopropenes Leading to Alkenyl Nitriles and Polycyclic Aromatic Compounds
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We report herein a radical-mediated amination of cyclopropenes. The transformation proceeds through a cleavage of the three-membered ring after the addition of an azide radical on the strained double bond and leads to tetrasubstituted alkenyl nitrile derivatives upon loss of N2. With 1,2-diaryl substituted cyclopropenes, this methodology could be extended to a one-pot synthesis of highly functionalized polycyclic aromatic compounds (PACs). This transformation allows the synthesis of nitrile-substituted alkenes and aromatic compounds from rapidly accessed cyclopropenes using only commercially available reagents.
- Muriel, Bastian,Waser, Jerome
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supporting information
p. 4075 - 4079
(2021/01/18)
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- Engineering Dirhodium Artificial Metalloenzymes for Diazo Coupling Cascade Reactions**
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Artificial metalloenzymes (ArMs) are commonly used to control the stereoselectivity of catalytic reactions, but controlling chemoselectivity remains challenging. In this study, we engineer a dirhodium ArM to catalyze diazo cross-coupling to form an alkene that, in a one-pot cascade reaction, is reduced to an alkane with high enantioselectivity (typically >99 % ee) by an alkene reductase. The numerous protein and small molecule components required for the cascade reaction had minimal effect on ArM catalysis. Directed evolution of the ArM led to improved yields and E/Z selectivities for a variety of substrates, which translated to cascade reaction yields. MD simulations of ArM variants were used to understand the structural role of the cofactor on ArM conformational dynamics. These results highlight the ability of ArMs to control both catalyst stereoselectivity and chemoselectivity to enable reactions in complex media that would otherwise lead to undesired side reactions.
- Bultman, Max J.,Huang, Rui,Lewis, Jared C.,Li, Ying,Roux, Benoit,Upp, David M.
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supporting information
p. 23672 - 23677
(2021/08/23)
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- Dirhodium(II)/Xantphos-Catalyzed Relay Carbene Insertion and Allylic Alkylation Process: Reaction Development and Mechanistic Insights
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Although dirhodium-catalyzed multicomponent reactions of diazo compounds, nucleophiles and electrophiles have achieved great advance in organic synthesis, the introduction of allylic moiety as the third component via allylic metal intermediate remains a formidable challenge in this area. Herein, an attractive three-component reaction of readily accessible amines, diazo compounds, and allylic compounds enabled by a novel dirhodium(II)/Xantphos catalysis is disclosed, affording various architecturally complex and functionally diverse α-quaternary α-amino acid derivatives in good yields with high atom and step economy. Mechanistic studies indicate that the transformation is achieved through a relay dirhodium(II)-catalyzed carbene insertion and allylic alkylation process, in which the catalytic properties of dirhodium are effectively modified by the coordination with Xantphos, leading to good activity in the catalytic allylic alkylation process.
- Liang, Xinyi,Lu, Bin,Peng, Qian,Wang, Xiaoming,Wang, Zijian,Zhang, Jinyu
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supporting information
p. 11799 - 11810
(2021/08/16)
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- Divergent Synthesis of Aziridine and Imidazolidine Frameworks under Blue LED Irradiation
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We develop a visible light-promoted divergent cycloaddition of α-diazo esters with hexahydro-1,3,5-triazines, leading to a series of aziridine and imidazolidine frameworks in average good yield, by simply changing the reaction media used. It is noteworthy that the reaction occurs under sole visible light irradiation without the need for exogenous photoredox catalysts. More significantly, a reasonable reaction mechanism was proposed on the basis of the control experiments and density functional theory calculation results.
- Cheng, Xiao,Cai, Bao-Gui,Mao, Hui,Lu, Juan,Li, Lei,Wang, Kun,Xuan, Jun
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supporting information
p. 4109 - 4114
(2021/05/26)
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- Visible-Light-Promoted Polysubstituted Olefins Synthesis Involving Sulfur Ylides as Carbene Trapping Reagents
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A blue-light-emitting diode (LED) promoted coupling of aryl diazoacetates with sulfur ylides is described. This protocol features mild conditions, good functional group tolerance, and broad substrate scope for both aryl diazoacetates with sulfur ylides. Under optimal reaction conditions, a wide range of trisubstituted olefins is obtained in moderate to good yield, which can be further transferred to other biologically important heterocycles after a two-step simple operation.
- Ye, Cong,Cai, Bao-Gui,Lu, Juan,Cheng, Xiao,Li, Lei,Pan, Zhong-Wen,Xuan, Jun
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p. 1012 - 1022
(2021/01/09)
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- Photoinduced Diverse Reactivity of Diazo Compounds with Nitrosoarenes
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A diverse reactivity of diazo compounds with nitrosoarene in an oxygen-transfer process and a formal [2 + 2] cycloaddition is reported. Nitosoarene has been exploited as a mild oxygen source to oxidize an in situ generated carbene intermediate under visible-light irradiation. UV-light-mediated in situ generated ketenes react with nitosoarenes to deliver oxazetidine derivatives. These operationally simple processes exemplify a transition-metal-free and catalyst-free protocol to give structurally diverse α-ketoesters or oxazetidines.
- Roy, Sourav,Kumar, Gourav,Chatterjee, Indranil
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supporting information
p. 6709 - 6713
(2021/09/08)
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- Blue Light-Emitting Diode-Mediated in Situ Generation of Pyridinium and Isoquinolinium Ylides from Aryl Diazoesters: Their Application in the Synthesis of Diverse Dihydroindolizine
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Blue light-emitting diode-mediated environmentally sustainable three component reactions among pyridine/isoquinoline 1/2, aryl diazoesters 3, and acrylic ester/3-alkenyl oxindoles 5/6 provide various dihydroindolizines 7 to 9 in excellent yield. The principle of the strategy is photolytic generation of nitrogen ylides from N-heteroarenes and aryl diazoesters and their subsequent [3 + 2] cycloaddition reaction with dipolarophiles. Detailed mechanistic analysis of the transformation through control experiments establishes this strategy as the foundation for the photolytic multicomponent reaction.
- Guha, Souvik,Maiti, Debajit,Prabakar, Tejas,Sar, Saibal,Sen, Subhabrata
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p. 11736 - 11747
(2021/09/02)
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- Blue Light-Promoted N?H Insertion of Carbazoles, Pyrazoles and 1,2,3-Triazoles into Aryldiazoacetates
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Blue light irradiation of aryldiazoacetates leads to the formation of free carbenes, which can react with carbazoles, pyrazoles and 1,2,3-triazoles to afford the corresponding N?H inserted products. These reactions are performed under air and at room temperature, allowing the mild preparation of a variety of motifs found in biologically relevant targets. (Figure presented.).
- Stivanin, Mateus L.,Fernandes, Alessandra A. G.,da Silva, Amanda F.,Okada, Celso Y.,Jurberg, Igor D.
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p. 1106 - 1111
(2020/01/25)
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- Room Temperature Coupling of Aryldiazoacetates with Boronic Acids Enhanced by Blue Light Irradiation
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A visible-light-promoted photochemical protocol is reported for the coupling of aryldiazoacetates with boronic acids. This photochemical reaction shows great enhancement compared to the same protocol performed in the absence of light. Except for a few cases, the room temperature coupling in the dark (thermal process) generally does not work. When it does, it is likely to also involve free carbenes as key intermediates. Alternatively, photochemical reactions show a broad scope, can be performed under air and tolerate a wide variety of functional groups. Reaction-evolution monitoring, DFT calculations and control experiments have been used to evaluate the main aspects of this intricate mechanistic scenario. Biologically active molecules Adiphenine, Benactyzine and Aprophen have been prepared as examples of synthetic applications.
- da Silva, Amanda F.,Afonso, Marco A. S.,Cormanich, Rodrigo A.,Jurberg, Igor D.
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p. 5648 - 5653
(2020/04/22)
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- Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
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The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadienes, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) carbene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones to afford alcohol-, amine-, or aniline-containing 1,3-dienes in moderate to high yields and with excellent stereoselectivity. This protocol features operational simplicity, mild reaction conditions, a broad substrate scope, and gram-scalability. Notably, a structurally unique allylic Pd(II) intermediate was isolated and characterized. DFT calculation and control experiments demonstrated that a rare Pd(0) carbene intermediate could be involved in this reaction. Moreover, the polysubstituted butadienes as novel building blocks were unprecedentedly assembled into macrocycles, which efficiently inhibited the P-glycoprotein and dramatically reversed multidrug resistance in cancer cells by 190-fold.
- Chen, Xiangyang,Hao, Jiping,Houk, K. N.,Li, Yingzi,Lou, Liguang,Quan, Haitian,Song, Bichao,Wang, Lu,Xia, Yuanzhi,Xie, Peipei,Xu, Zhongliang,Yang, Weibo
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p. 9982 - 9992
(2020/06/27)
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- Borane-Catalyzed Stereoselective C–H Insertion, Cyclopropanation, and Ring-Opening Reactions
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Lewis acidic boranes have been shown to be effective metal-free catalysts for highly selective reactions of donor-acceptor diazo compounds to a range of substrates. The reactions of α-aryl α-diazoesters with nitrogen heterocycles indole or pyrrole selectively generate C3 and C2 C–H insertion products, respectively, in good to excellent yields even when using unprotected indoles. Alternatively, benzofuran, indene, and alkene substrates give exclusively cyclopropanated products with α-aryl α-diazoesters, whereas the reactions with furans lead to ring-opening. Comprehensive theoretical calculations have been used to explain the differing reactivities and high selectivities of these reactions. Overall, this work demonstrates the selective metal-free catalytic reactions of α-aryl α-diazoesters with (hetero)cycles and alkenes. This simple, mild reaction protocol represents an alternative to the commonly used precious metal systems and may provide future applications in the generation of biologically active compounds. Efficient and facile routes to heterocyclic compounds are highly desirable because of their remarkable biological importance and applications in drugs approved by the Food and Drug Administration. Current synthetic routes frequently use precious metal-catalyzed reactions. The problems associated with the limited resources of precious metals as well as their toxicities can be avoided through metal-free approaches. Our investigations on the reactivities of diazoesters toward the (hetero)arenes reveal that by using Lewis acidic triarylboranes as a catalyst, we can selectively effect C–H insertion, cyclopropanation, or ring-opening in good to excellent yields. Main group, or metal-free, catalysis has become a burgeoning field; yet, this flourishing field is still in its nascent stage. The work described herein represents a step toward improving the applicability of main group catalysis by employing metal-free approaches in the functionalization of organic compounds. This work demonstrates the highly selective metal-free catalytic reactions of α-aryl α-diazoesters with a range of (hetero)cycles and olefins using Lewis acidic boranes. The simple, mild reaction protocol employed represents an alternative to the commonly used precious metal systems and may provide future applications in the generation of biologically active compounds.
- Dasgupta, Ayan,Babaahmadi, Rasool,Slater, Ben,Yates, Brian F.,Ariafard, Alireza,Melen, Rebecca L.
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supporting information
p. 2364 - 2381
(2020/08/14)
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- Photochemical Doyle-Kirmse Reaction: A Route to Allenes
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This Letter describes the metal-free, blue-light-induced [2,3]-sigmatropic rearrangement of sulfonium ylides generated from donor/acceptor diazoalkanes and propargyl sulfides. The reaction furnishes highly functionalized allenes from a broad range of starting materials in decent yield. Mechanistic experiments supported by the literature data suggest singlet carbenes as intermediates in this reaction.
- Or?owska, Katarzyna,Rybicka-Jasińska, Katarzyna,Krajewski, Piotr,Gryko, Dorota
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supporting information
p. 1018 - 1021
(2020/01/31)
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- Diazo Activation with Diazonium Salts: Synthesis of Indazole and 1,2,4-Triazole
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A donor/acceptor diazo activation strategy, processing via condensation using diazonium salts without the addition of any other catalysts or reagents, is reported. The diazenium intermediate was found to undergo cyclization to give indazoles in excellent yields. Alternatively, in the presence of nitriles, substituted 1,2,4-triazoles were obtained in good to excellent yields. This interesting diazenium route provides a new approach to achieve complex heterocycle synthesis under mild conditions.
- Li, Xuming,Ye, Xiaohan,Wei, Chiyu,Shan, Chuan,Wojtas, Lukasz,Wang, Qilin,Shi, Xiaodong
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supporting information
p. 4151 - 4155
(2020/06/05)
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- Diastereoselective Trapping of Transient Carboxylic Oxonium Ylides with α,β-Unsaturated 2-Acyl Imidazoles
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By developing a diastereoselective reaction of cyclopropene carboxylic acids with α,β-unsaturated 2-acyl imidazoles, we reported here a Michael-type trapping of transient carboxylic oxonium ylides. This transformation provides a direct approach for the construction of valuable γ-butenolide derivatives in good yields (60–99%) with high diastereoselectivities (up to >95:5 dr) under mild reaction conditions. (Figure presented.).
- Zhang, Mengchu,Zhang, Tianyuan,Zhang, Dan,Hu, Wenhao
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supporting information
p. 4662 - 4667
(2020/09/23)
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- Visible-Light-Mediated S?H Bond Insertion Reactions of Diazoalkanes with Cysteine Residues in Batch and Flow
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We describe the application of S?H bond insertion reactions of aryl diazoacetates with cysteine residues that enabled metal-free, S?H functionalization under visible-light conditions. Moreover, this process could be intensified by a continuous-flow photomicroreactor on the acceleration of the reaction (6.5 min residence time). The batch and flow protocols described were applied to obtain a wide range of functionalized cysteine derivatives and cysteine-containing dipeptides, thus providing a straightforward and general platform for their functionalizations in mild conditions. (Figure presented.).
- Chen, Lin,Cui, Yu-Sheng,Duan, Xiu,Guo, Kai,Qin, Long-Zhou,Qiu, Jiang-Kai,Sun, Qi,Yuan, Xin,Zhuang, Kai-Qiang
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supporting information
p. 5093 - 5104
(2020/09/23)
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- Metal-Free Tandem Rearrangement/Lactonization: Access to 3,3-Disubstituted Benzofuran-2-(3H)-ones
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A novel metal-free synthesis of 3,3-disubstituted benzofuran-2-(3H)-ones through reacting α-aryl-α-diazoacetates with triarylboranes is presented. Initially, triarylboranes were successfully investigated in α-arylations of α-diazoacetates, however in the presence of a heteroatom in the ortho position, the boron enolate intermediate undergoes an intramolecular rearrangement to form a quaternary center. The intermediate cyclizes to afford valuable 3,3-disubstituted benzofuranones in good yields.
- Santi, Micol,Ould, Darren M. C.,Wenz, Jan,Soltani, Yashar,Melen, Rebecca L.,Wirth, Thomas
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p. 7861 - 7865
(2019/04/25)
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- Convenient Approach to 2-Substituted (Thio)morpholin-3-ones from α-Diazoacetates via X-H Carbene Insertion – Lactamization Sequence
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Stepwise coupling of N-Boc-protected β-aminoethanols or β-mercaptoethylamines with various α-diazoacetates provides a new, unified approach to constructing (thio)morpholin-3-ones. The process involves a Rh2(esp)2-catalyzed X-H insert
- Solovyov, Igor,Dar'in, Dmitry,Krasavin, Mikhail
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p. 7432 - 7438
(2019/11/28)
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- Iron and Ruthenium Glycoporphyrins: Active Catalysts for the Synthesis of Cyclopropanes and Aziridines
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In view of the relevance of cyclopropanes and aziridines as synthetic building blocks as well as active parts in biological and pharmaceutical compounds, the development of sustainable synthetic procedures for obtaining these products continues to be a si
- Damiano, Caterina,Gadolini, Sebastiano,Intrieri, Daniela,Lay, Luigi,Colombo, Cinzia,Gallo, Emma
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supporting information
p. 4412 - 4420
(2019/11/03)
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- Rhodium(II)-Catalyzed Regioselective C3-Alkylation of 2-Arylimidazo[1,2-a]pyridines with Aryl Diazoesters
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A regioselective C3-alkylation based on the reaction of 2-arylimidazo[1,2-a]pyridines with a wide range of aryl α-diazoesters in the presence of a Rh(II) catalyst in dichloroethane at room temperature was developed. This method could be applied in the synthesis of benzoimidazoquinolizinone and cycloheptaimidazopyridinone, which are novel heterocyclic scaffolds. (Figure presented.).
- Kim, Hyunseok,Byeon, Minhyeon,Jeong, Eunchong,Baek, Yonghyeon,Jeong, Seung Jin,Um, Kyusik,Han, Sang Hoon,Han, Gi Uk,Ko, Gi Hoon,Maeng, Chanyoung,Son, Jeong-Yu,Kim, Dongwook,Kim, Sung Hong,Lee, Kooyeon,Lee, Phil Ho
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supporting information
p. 2094 - 2106
(2019/03/21)
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- Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
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We report a bifunctional Ag catalyst promoted intramolecular capture of oxonium ylides with alkynes for the enantioselective synthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with respect to 9, suggesting that two molecules of 9 are involved in the intramolecular trapping of a Ag-associated oxonium ylide with a Ag-activated alkyne. Based on our mechanistic hypothesis, we further optimized the reaction, rendering a facile approach to 2,5-dihydrofurans in good to excellent yields in a highly chemo- and enantioselective fashion.
- Shi, Taoda,Teng, Shenghan,Gopi Krishna Reddy, Alavala,Guo, Xin,Zhang, Yueteng,Moore, Kohlson T.,Buckley, Thomas,Mason, Damian J.,Wang, Wei,Chapman, Eli,Hu, Wenhao
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supporting information
p. 8737 - 8744
(2019/10/16)
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- Photoredox Decarboxylative C(sp3)-N Coupling of α-Diazoacetates with Alkyl N-Hydroxyphthalimide Esters for Diversified Synthesis of Functionalized N-Alkyl Hydrazones
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Herein we report a metal-free photocatalytic coupling reaction for the synthesis of structurally and functionally diverse N-alkyl hydrazones from α-diazoacetates and N-alkyl hydroxyphthalimide esters. By employing Rose Bengal as a photocatalyst with yellow LEDs irradiation, over 60 N-alkyl hydrazones were synthesized. Fluorescence quenching analysis and deuterium incorporation experiments reveal that Hantzsch ester serves as both an electron donor and proton source for the reaction. This strategy offers a simple retrosynthetic disconnection for conventionally inaccessible C(sp3)-rich N-alkyl hydrazones.
- Chan, Chun-Ming,Xing, Qi,Chow, Yip-Chi,Hung, Sing-Fung,Yu, Wing-Yiu
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supporting information
p. 8037 - 8043
(2019/10/11)
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- A sustainable catalytic enantioselective synthesis of norstatine derivatives
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Norstatine derivatives are of important value in pharmaceutical science. However, their catalytic asymmetric synthesis is rare. We developed a sustainable method via chiral phosphoric acid (CPA)-[Rh(OAc)2]2 co-catalyzed multi-component reactions (MCR) of diazoacetates with alcohol/water and imines. This method allows us to synthesize a library of 45 norstatines with excellent enanotioselectivites and broad substrate scope which includes anti-α-aryl-norstatines 11-1, anti-α-alkyl-norstatines 11-2, syn-α-hydro-norstatines 11-3 and syn-α-aryl-norstatines 11-4. The sustainability of this method lies in the reliable scalability, improved safety, and reusable [Rh(OAc)2]2 catalyst. The synthetic value of norstatine derivatives was demonstrated by preparing oxazolinone 14, ezetimibe analogue 15, and Taxol C-13 chain 16. Mechanistic study reveals that the synergetic catalysis of CPA and [Rh(OAc)2]2 is essential to maintain chemo- and enantioselectivity. Control experiments support the mechanism where the reactions proceed through the trapping of hyper-reactive oxonium ylides with imines. Shortly, we report herein the sustainable catalytic enantioselective synthesis of both syn- and anti-norstatine derivatives. We believe that this method might shed light on the sustainable synthesis of norstatine derivative-based drug candidates.
- Shi, Taoda,Jing, Changcheng,Qian, Yu,Xu, Xinfang,Alavala, Gopi Krishna Reddy,Lv, Xinxin,Hu, Wenhao
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supporting information
p. 9792 - 9798
(2019/12/02)
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- Pd-Catalyzed Three-Component Domino Reaction of Vinyl Benzoxazinanones for Regioselective and Stereoselective Synthesis of Allylic Sulfone-Containing Amino Acid Derivatives
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A Pd-catalyzed, highly regioselective and stereoselective three-component domino allylic substitution/N-H carbene insertion reaction under mild conditions is described. This reaction demonstrates a wide substrate scope and satisfactory functional group tolerance, providing a broad range of allylic sulfone-containing amino acid derivatives. Moreover, DBU mediates highly diastereoselective cross-dehydrogenative coupling annulation of allylic sulfones without using peroxides or any metal oxidants. This developed protocol affords 7-membered ring heterocyclic compounds incorporating both sulfone-containing amino acid esters and one quaternary carbon center. Mechanistic studies indicate that an unusual umpolung of glycine occurred in this annulation.
- Hao, Jiping,Xu, Yi,Xu, Zhongliang,Zhang, Zhiqiang,Yang, Weibo
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p. 7888 - 7892
(2019/01/04)
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- Silica-supported HClO4 promotes catalytic solvent- and metal-free O-H insertion reactions with diazo compounds
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Solvent-free O-H insertion reactions in the presence of diazo carbonyl compounds were carried-out in very mild conditions. Unlike the traditional metal-catalysed version, employing rhodium acetate dimer, this method uses eco-friendly silica-supported HClO4 as the catalyst. Only 0.3 mol% of this Br?nsted acid catalyst, that can also be recycled several times, is necessary to guarantee very good yields (up to 97%) in the O-H insertion reactions. Reaction set-up is simple and permitted the preparation of forty-three α-hydroxy and α-alkoxy esters/ketones in just 1 h and at room temperature.
- Gallo, Rafael Douglas C.,Burtoloso, Antonio C. B.
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p. 4547 - 4556
(2018/10/17)
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- Method for synthesizing alpha-diazoesters compound by using microwave at normal pressure
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The invention discloses a method for synthesizing an alpha-diazoesters compound by using microwave at normal pressure. An esters compound and P-toluenesulfonyl azide are used as initial raw materials,1,8-diazabicyclo[5.4.0]undec-7-ene(DBU) is used as a catalyst, the alpha-diazoesters compound can be generated in 30 minutes by virtue of a diazo transfer reaction under a microwave assisting heating condition, and the alpha-diazoesters compound can further generate a functional product. The organic reaction rate of the method is multiple times faster than the traditional heating method, the reaction efficiency is high, the operation is simple and convenient, the synthetic reaction condition is mild, the product type is rich, and the functional group is diversified.
- -
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Paragraph 0044-0046
(2018/11/22)
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- Synthesis of γ-Sulfur-Substituted Ketones via Rh(II)/Sc(III) a Cocatalyzed Three-Component Reaction of Diazo Compounds with Thiophenols and Enones
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A facile method for the synthesis of γ-sulfur-substituted ketones is developed via a Rh(II)/Sc(III) cocatalyzed three-component reaction of diazo compounds with thiophenols and enones. With this method, different γ-sulfur-substituted ketones were obtained
- Xiao, Guolan,Ma, Chaoqun,Wu, Xiang,Xing, Dong,Hu, Wenhao
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p. 4786 - 4791
(2018/04/26)
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- Au Nanoparticle-Catalyzed Insertion of Carbenes from α-Diazocarbonyl Compounds into Hydrosilanes
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Supported Au nanoparticles on TiO2 catalyze the insertion of carbenes from α-diazocabonyl compounds into hydrosilanes. It is proposed that the transformation involves two modes of catalytic activation: formation of nucleophilic Au carbenes on the surface of nanoparticle via expulsion of N2 and activation of the Si-H bond of hydrosilane on Au nanoparticle, followed by coupling of the chemisorbed species. No external ligands or additives are required, while the process is purely heterogeneous, thus allowing the recycling and reuse of the catalyst.
- Kidonakis, Marios,Stratakis, Manolis
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supporting information
p. 4086 - 4089
(2018/07/15)
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- Copper-Catalyzed Carbenoid Insertion Reactions of α-Diazoesters and α-Diazoketones into Si-H and S-H Bonds
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An efficient copper-catalyzed carbenoid insertion reaction of α-diazo carbonyl compounds into Si-H and S-H bonds was developed. A wide range of α-silylesters and α-thioesters was obtained in high yields (up to 98%) from α-diazoesters using 5 mol% of a simple copper(I) salt as catalyst. Using 0.05 mol% of the same catalyst, α-diazoketones led to α-silylketones in low to good yields (up to 70%).
- Keipour, Hoda,Jalba, Angela,Delage-Laurin, Léo,Ollevier, Thierry
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p. 3000 - 3010
(2017/03/23)
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- Iron-Catalyzed Carbene Insertion Reactions of α-Diazoesters into Si-H Bonds
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An efficient iron-catalyzed carbene insertion reaction of α-diazo carbonyl compounds into the Si-H bond was developed. A wide range of α-silylesters was obtained in high yields (up to 99%) from α-diazoesters using a simple iron(II) salt as catalyst.
- Keipour, Hoda,Ollevier, Thierry
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supporting information
p. 5736 - 5739
(2017/11/10)
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- Enantioselective Palladium-Catalyzed Carbene Insertion into the N?H Bonds of Aromatic Heterocycles
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C3-substituted indoles and carbazoles react with α-aryl-α-diazoesters under palladium catalysis to form α-(N-indolyl)-α-arylesters and α-(N-carbazolyl)-α-arylesters. The products result from insertion of a palladium-carbene ligand into the N?H bond of the aromatic N-heterocycles. Enantioselection was achieved using a chiral bis(oxazoline) ligand, in many cases with high enantioselectivity (up to 99 % ee). The method was applied to synthesize the core of a bioactive carbazole derivative in a concise manner.
- Arredondo, Vanessa,Hiew, Stanley C.,Gutman, Eugene S.,Premachandra, Ilandari Dewage Udara Anulal,Van Vranken, David L.
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supporting information
p. 4156 - 4159
(2017/04/03)
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- Development of a simple system for the oxidation of electron-rich diazo compounds to ketones
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Mild heating of diazo compounds in DMSO furnishes ketone products in moderate to excellent yields. The reaction is particularly effective on electron-rich substrates and exhibits high chemoselectivity, allowing for the use of diazo compounds containing additional oxidation-prone functional groups. This straightforward protocol offers an alternate route to synthetically useful α-ketoesters from readily available aryl diazoacetates.
- O'Connor, Nicholas R.,Bolgar, Peter,Stoltz, Brian M.
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p. 849 - 851
(2016/02/05)
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- Cyclopropenation of internal alkynylsilanes and diazoacetates catalyzed by copper(i) N-heterocyclic carbene complexes
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Copper(i) N-heterocyclic carbene (CuNHC) complexes are more catalytically active than traditional transition metal salts for the cyclopropenation of internal alkynylsilanes and diazoacetate compounds. A series of 1,2,3-trisubstituted and 1,2,3,3-tetrasubstituted cyclopropenylsilane compounds were isolated in good overall yields. An interesting regioselective and chemodivergent reaction pathway was also observed to furnish a tetra-substituted furan for an electron-rich donor/acceptor diazoacetate. Finally, a practical synthesis of a cyclopropenyl-containing starting material that is useful for bioorthogonal chemistry is also described.
- Thomas, Thomas J.,Merritt, Benjamin A.,Lemma, Betsegaw E.,McKoy, Adina M.,Nguyen, Tri,Swenson, Andrew K.,Mills, Jeffrey L.,Coleman, Michael G.
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supporting information
p. 1742 - 1747
(2016/02/10)
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- The Rh(II)-catalyzed formal N-S bond insertion reaction of aryldiazoacetates into: N -phenyl-sulfenyl phthalimide
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The Rh(ii)-catalyzed sulfur ylide [1,2]-rearrangement of carbenoids generated from aryldiazoacetates has been realized via N-S bond insertion, generating tertiary sulfides in moderate to excellent yields. This demonstrates the first use of the sulfur ylide [1,2]-rearrangement undergoing N-S bond insertion. This protocol could proceed smoothly with high regioselectivity, low catalyst loading (0.1 mol% Rh2(OAc)4), gram-scale reaction and broad substrate scope. And the product could be converted into glycine derivatives through simple procedures.
- Song, Zhuang,Wu, Yizhou,Xin, Tao,Jin, Chao,Wen, Xiaoan,Sun, Hongbin,Xu, Qing-Long
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supporting information
p. 6079 - 6082
(2016/05/19)
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- Catalyst-Free S–S Bond Insertion Reaction of a Donor/Acceptor-Free Carbene by a Radical Process: A Combined Experimental and Computational Study
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Herein, a donor/acceptor-free carbene insertion reaction of an S–S bond through a radical process is presented. This catalyst-free reaction was thermally induced and provided the dithioketal products in moderate to high yields. A mechanism involving radical intermediates was proposed according to the computational study, and these intermediates were verified experimentally and intercepted for the first time by using a cross-coupling reaction.
- Zheng, Yang,Bian, Rongjian,Zhang, Xiaolu,Yao, Ruwei,Qiu, Lihua,Bao, Xiaoguang,Xu, Xinfang
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supporting information
p. 3872 - 3877
(2016/08/16)
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- Borosilicate Activation of (Difluoroiodo)toluene in the gem-Difluorination of Phenyldiazoacetate Derivatives
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A combined experimental and computational investigation was conducted to identify a mild and effective Lewis-acidic activator for TolIF2in the gem-difluorination of diazo compounds. Computationally, borosilicate, a common constituent of laborat
- Sinclair, Geoffrey S.,Tran, Richard,Tao, Jason,Hopkins, W. Scott,Murphy, Graham K.
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supporting information
p. 4603 - 4606
(2016/09/28)
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- Copper-Catalyzed Regiospecific and 1,2-Regioselective Cyclopropanation of (1 Z)-1-Amino- and (1 Z)-1-Oxy-1,3-butadienyl Derivatives
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The copper-catalyzed regiospecific and 1,2-regioselective cyclopropanation of (1Z)-1-amino- and (1Z)-1-oxy-1,3-butadienyl derivatives, which could be prepared by Z-stereoselective 1,4-elimination with α-aryl diazoesters was successfully demonstrated. This successful regiospecific protocol enabled the preparation of the corresponding 1-amino- and 1-oxy-2-vinylcyclopropane derivatives as almost single stereoisomers.
- Tayama, Eiji,Saito, Shun
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p. 1880 - 1884
(2015/08/06)
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- Copper-catalyzed oxygen atom transfer of N-oxides leading to a facile deoxygenation procedure applicable to both heterocyclic and amine N-oxides
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Deoxygenation of various types of N-oxides including both heterocyclic and alkyl(aryl)amine derivatives has successfully been developed by the copper-catalyzed oxygen atom transfer using diazo compounds as the oxygen acceptor. The reaction proceeds smoothly over a broad range of substrates with excellent functional group tolerance under mild conditions. This journal is
- Jeong, Jisu,Lee, Donggun,Chang, Sukbok
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supporting information
p. 7035 - 7038
(2015/04/22)
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- Pd(ii)-catalyzed formal [4+1] cycloaddition reactions of diazoacetates and aryl propargyl alcohols to form 2,5-dihydrofurans
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A Pd(ii)-catalyzed formal [4+1] cycloaddition of aryl diazoacetates and aryl propargyl alcohols is reported to afford 2,5-dihydrofuran derivatives as the dominant product over other traditional ones. The auto-tandem catalytic process is proposed to occur via Pd(ii)-catalyzed intermolecular oxonium ylide formation and subsequent intramolecular trapping of the ylide with Pd(ii)-activated alkynes.
- Shi, Taoda,Guo, Xin,Teng, Shenghan,Hu, Wenhao
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supporting information
p. 15204 - 15207
(2015/10/12)
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- Copper(II)-acid catalyzed cyclopropanation of 1,3-dienamides by electrophilic activation of α-aryl diazoesters
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Copper(II)-acid catalyzed cyclopropanation of electron-rich alkenes, such as 1,3-dienamides, with α-aryl diazoesters are described. The reaction could be performed without rare metal catalysts, excess substrate, or the need for the slow addition of the diazoesters.
- Tayama, Eiji,Horikawa, Kouki,Iwamoto, Hajime,Hasegawa, Eietsu
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supporting information
p. 3041 - 3044
(2014/05/20)
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- Three-component reactions based on trapping ammonium ylides with N-sulfonyl aldimines via cooperative catalysis of squaramides and Rh2(OAc) 4
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Three-component reactions of aryl diazoacetates, arylamines and N-sulfonyl aldimines cooperatively catalyzed by squaramides and dirhodium acetate are reported to afford N-sulfonyl α,β-diamino acid derivatives in moderate to good yields and diastereoselect
- Qiu, Lin,Wang, Dongwei,Lv, Fengping,Guo, Xin,Hu, Wenhao,Yang, Liping,Liu, Shunying
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supporting information
p. 1471 - 1477
(2014/02/14)
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- CuO/SiO2 as a simple, effective and recoverable catalyst for alkylation of indole derivatives with diazo compounds
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The purely inorganic copper oxide on silica catalyzes the reaction of methyl phenyldiazoacetate with N-methyl indole under mild reaction conditions, giving the alkylation (formally a C-H insertion) in position 3, and the catalyst can be recovered and reused at least in 5 consecutive runs with only minor loss in activity. The scope of the reaction includes various diazo compounds and indole or pyrrole derivatives leading to alkylation or cyclopropanation depending on the heterocycle structure. An alternative mechanism, without reduction of Cu(ii) to Cu(i), is proposed on the basis of the obtained results. The Royal Society of Chemistry 2013.
- Fraile, Jose M.,Le Jeune, Karel,Mayoral, Jose A.,Ravasio, Nicoletta,Zaccheria, Federica
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supporting information
p. 4327 - 4332
(2013/08/23)
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- Synthesis, structural analysis, and catalytic properties of tetrakis(binaphthyl or octahydrobinaphthyl phosphate) dirhodium(II,II) complexes
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The X-ray structural analyses of homoleptic Rh(II) complexes made of enantiopure (R)-1,1′-binaphthyl and (R)-(5,5′,6,6′,7,7′, 8,8′-octahydro)binaphthyl phosphate ligands are for the first time presented. The possibility to introduce halogen atoms at the 3,3′-positions is also reported. The isolated dirhodium complexes were further tested as catalysts (1 mol %) in enantioselective cyclopropanations and Si-H insertion reactions, affording chiral cyclopropanes and silanes in good yield but moderate enantioselectivity (ee max 63%).
- Hrdina, Radim,Guenee, Laure,Moraleda, Delphine,Lacour, Jeroime
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supporting information
p. 473 - 479
(2013/03/28)
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- Guide to enantioselective dirhodium(II)-catalyzed cyclopropanation with aryldiazoacetates Dedicated to Professor Melanie Sanford in recognition of her receipt of the Tetrahedron Young Investigator Award
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Catalytic enantioselective methods for the generation of cyclopropanes have been of long standing pharmaceutical interest. Chiral dirhodium(II) catalysts prove to be an effective means for the generation of diverse cyclopropane libraries. Rh2(R-DOSP)4 is generally the most effective catalyst for asymmetric intermolecular cyclopropanation of methyl aryldiazoacetates with styrene. Rh2(S-PTAD)4 provides high levels of enantioinduction with ortho-substituted aryldiazoacetates. The less-established Rh2(R-BNP)4 plays a complementary role to Rh2(R-DOSP)4 and Rh2(S-PTAD)4 in catalyzing highly enantioselective cyclopropanation of 3-methoxy substituted aryldiazoacetates. Substitution on the styrene has only moderate influence on the asymmetric induction of the cyclopropanation.
- Chepiga, Kathryn M.,Qin, Changming,Alford, Joshua S.,Chennamadhavuni, Spandan,Gregg, Timothy M.,Olson, Jeremy P.,Davies, Huw M.L.
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supporting information
p. 5765 - 5771
(2013/07/05)
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- TAK1 KINASE INHIBITORS, COMPOSITIONS, AND USED RELATED THERETO
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The disclosure relates to TAK1 inhibitors, compositions, and uses related thereto. In certain embodiments, the disclosure relates to compounds of formula (I), pharmaceutical compositions having a compound of formula (I), and methods of treating or prevent
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Page/Page column 24; 25
(2013/03/26)
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