- Enantioselective intramolecular cyclization of alkynyl esters catalyzed by a chiral Br?nsted base
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An enantioselective intramolecular cyclization reaction of alkynyl esters was developed, which employs a Br?nsted base catalyst generated in situ from a chiral Schiff base and t-BuOK. This reaction is a rare example of the enantioselective intramolecular addition of simple ester enolates to alkynes under Br?nsted base catalysis.
- Kondoh, Azusa,Tran, Hoa Thi Quynh,Kimura, Kyoko,Terada, Masahiro
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supporting information
p. 5726 - 5729
(2016/05/19)
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- Dual Photoredox/Gold Catalysis Arylative Cyclization of o-Alkynylphenols with Aryldiazonium Salts: A Flexible Synthesis of Benzofurans
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A new method for the arylative cyclization of o-alkynylphenols with aryldiazonium salts via dual photoredox/gold catalysis is described. The reaction proceeds smoothly at room temperature in the absence of base and/or additives and offers an efficient app
- Xia, Zhonghua,Khaled, Omar,Mouriès-Mansuy, Virginie,Ollivier, Cyril,Fensterbank, Louis
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p. 7182 - 7190
(2016/08/30)
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- Alkyne Carbonyl Metathesis As a Means to Make 4-Acyl Chromenes: Syntheses of (±)-Deguelin and (±)-Munduserone
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A highly convergent synthetic approach to rotenoid natural products is described. Successful pairing of two building blocks for Sonogashira cross-coupling and intramolecular alkyne carbonyl metathesis allows ready access to 4-acylchromene, a key substruct
- Nayak, Maloy,Kim, Ikyon
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p. 11460 - 11467
(2015/12/01)
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- Palladium-Catalyzed One-Pot Reaction of Hydrazones, Dihaloarenes, and Organoboron Reagents: Synthesis and Cytotoxic Activity of 1,1-Diarylethylene Derivatives
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A new three-component assembly reaction between N-tosylhydrazones, dihalogenated arenes, and boronic acids or boronate esters was developed, producing highly substituted 1,1-diarylethylenes in good yields. The two C-C bonds formed through this coupling ha
- Roche, Maxime,Salim, Salim Mmadi.,Bignon, Jér?me,Levaique, Hélène,Brion, Jean-Daniel,Alami, Mouad,Hamze, Abdallah
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p. 6715 - 6727
(2015/10/06)
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- SYSTEM FOR CONTROLLING THE REACTIVITY OF BORONIC ACIDS
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A protected organoboronic acid includes a boron having an sp3 hybridization, a conformationally rigid protecting group bonded to the boron, and an organic group bonded to the boron through a boron-carbon bond. A method of performing a chemical reaction includes contacting a protected organoboronic acid with a reagent, the protected organoboronic acid including a boron having an sp3 hybridization, a conformationally rigid protecting group bonded to the boron, and an organic group bonded to the boron through a boron-carbon bond. The organic group is chemically transformed, and the boron is not chemically transformed.
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Page/Page column 15
(2009/02/11)
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- A simple and modular strategy for small molecule synthesis: Iterative Suzuki-Miyaura coupling of B-protected haloboronic acid building blocks
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We herein describe a simple and highly modular strategy for small molecule synthesis involving the iterative cross-coupling of B-protected bifunctional haloboronic acids. Enabling this approach, we have newly discovered that the pyramidalization of boroni
- Gillis, Eric P.,Burke, Martin D.
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p. 6716 - 6717
(2008/02/05)
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- Synthesis of constrained arylpiperidines using intramolecular Heck or radical reactions
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Two intramolecular routes were experimented to reach the hexahydrobenzofuro[2,3-c]pyridine platform: a Heck and a radical reaction. The radical route was applicable to all substrates, whereas the Heck route was of limited use. The key adducts were obtained via a Mitsunobu condensation between halogenated phenols and an allylic alcohol, the 3-hydroxy-tetrahydropyridine.
- Morice, Christophe,Domostoj, Mathias,Briner, Karin,Mann, André,Suffert, Jean,Wermuth, Camille-Georges
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p. 6499 - 6502
(2007/10/03)
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- Cyclization of o-(3-hydroxy-3-methylbutynyl)-phenols with boron tribromide to 4-bromo-2,2-dimethylchromenes and their electroreduction to 2,2-dimethylchromenes
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Cyclization of o-(3-hydroxy-3-methylbutynyl)phenols (2) with boron tribromide gave easily 4-bromo-2,2-dimethylchromenes (3). Electrolytic reduction of 3 at a Hg-pool electrode afforded the corresponding 2,2-dimethylchromenes (6) in high yields.
- Tsukayama, Masao
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p. 1131 - 1142
(2007/10/03)
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- REGIOSELECTIVE METALLATIONS OF (METHOXYMETHOXY)ARENES
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The methoxymethoxy substituent when attached to an aromatic ring functions as a moderately strong ortho-directing group in hydrogen-metal exchenge reactions.In many cases the propensity of the methoxymethoxylated arene toward ring metallations is greatly enhanced with concomitant suppression of undesirable side reactions such as nucleophilic attack and addition of metallating species.Unlike many other ortho-directing groups, the regio-direction of the methoxymethoxy substituent when in conjunction with other weaker directing groups is dependent upon the metallating medium.Thus, by changing the electron donating capacity of the metallating medium it is possible to selectively direct metallation to either of the positions ortho to the methoxymethoxy substituent.
- Ronald, Robert C.,Winkle, Mark R.
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p. 2031 - 2042
(2007/10/02)
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- Regioselective Metalation Reactions of Some Substituted (Methoxymethoxy)arenes
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The methoxymethoxy substituent acts as a relatively strong ortho-directing group in hydrogen-metal exchange reactions.However, the directing effects are influenced by the metalation medium, thus permitting an unusual degree of control of the site of metalation.In conjunction with weak ortho-directing groups, the metalation ortho to the methoxymethoxy group can be directed to either of the ortho positions by controlling the electron-donating capacity of the metalating solvent.In strongly donating solvents the 1,2,4-substitution pattern will arise from a meta-substituted methoxymethoxy arene, while in nondonating solvents the 1,2,3-substitution is favored.In addition, the methoxymethoxy group serves also to enhance the rate of metalation and to stabilize the aryl-metalated products so that some competing addition reactions are supressed.
- Winkle, Mark R.,Ronald, Robert C.
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p. 2101 - 2108
(2007/10/02)
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