- An Alternative and efficient route to chlorophacinone
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A straightforward synthesis for the anticoagulant rodenticide chlorophacinone is described. The short synthesis uses commercially available mandelic acid and 1,3-indanedione as staring materials.
- Csuk, Rene,Barthel, Alexander,Stroehl, Dieter
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- Visible-Light-Driven External-Reductant-Free Cross-Electrophile Couplings of Tetraalkyl Ammonium Salts
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Cross-electrophile couplings between two electrophiles are powerful and economic methods to generate C-C bonds in the presence of stoichiometric external reductants. Herein, we report a novel strategy to realize the first external-reductant-free cross-electrophile coupling via visible-light photoredox catalysis. A variety of tetraalkyl ammonium salts, bearing primary, secondary, and tertiary C-N bonds, undergo selective couplings with aldehydes/ketone and CO2. Notably, the in situ generated byproduct, trimethylamine, is efficiently utilized as the electron donor. Moreover, this protocol exhibits mild reaction conditions, low catalyst loading, broad substrate scope, good functional group tolerance, and facile scalability. Mechanistic studies indicate that benzyl radicals and anions might be generated as the key intermediates via photocatalysis, providing a new direction for cross-electrophile couplings.
- Liao, Li-Li,Cao, Guang-Mei,Ye, Jian-Heng,Sun, Guo-Quan,Zhou, Wen-Jun,Gui, Yong-Yuan,Yan, Si-Shun,Shen, Guo,Yu, Da-Gang
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p. 17338 - 17342
(2019/01/04)
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- Ruthenium-catalyzed umpolung carboxylation of hydrazones with CO2
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The first ruthenium-catalyzed umpolung carboxylation of hydrazones with CO2 to generate important aryl acetic acids is reported. Besides aldehyde hydrazones, a variety of ketone hydrazones, which have not been successfully applied in previous umpolung reactions with other reactive electrophiles, also show high reactivity and selectivity under mild conditions. Moreover, this operationally simple protocol features good functional group tolerance, is readily scalable, and offers easy derivation of important structures, including bioactive felbinac and adiphenine. Computational studies reveal that this umpolung reaction proceeds through the generation of a Ru-nitrenoid followed by concerted [4 + 2] cycloaddition with CO2.
- Yan, Si-Shun,Zhu, Lei,Ye, Jian-Heng,Zhang, Zhen,Huang, He,Zeng, Huiying,Li, Chao-Jun,Lan, Yu,Yu, Da-Gang
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p. 4873 - 4878
(2018/06/07)
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- Palladium-Catalyzed ?±-Arylation of Aryl Acetic Acid Derivatives via Dienolate Intermediates with Aryl Chlorides and Bromides
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To date, examples of ?±-arylation of carboxylic acids remain scarce. Using a deprotonative cross-coupling process (DCCP), a method for palladium-catalyzed ?3-arylation of aryl acetic acids with aryl halides has been developed. This protocol is applicable to a wide range of aryl bromides and chlorides. A procedure for the palladium-catalyzed ?±-arylation of styryl acetic acids is also described.
- Sha, Sheng-Chun,Zhang, Jiadi,Walsh, Patrick J.
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supporting information
p. 410 - 413
(2015/03/04)
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- Diastereoselectivity in the reduction of sterically unbiased 2,2-diarylcyclopentanones
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Reduction of sterically unbiased 2-phenyl-2-(4-X-phenyl)cyclopentanones 1 (X = NO2, Br, Cl, OCH3, OH, NH2) with either sodium borohydride in methanol or lithium borohydride in tetrahydrofuran at 0°C produced diastereomeric
- Halterman, Ronald L.,McEvoy, Marjorie A.
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p. 6690 - 6695
(2007/10/02)
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- COBALT-CATALYZED SYNTHESIS OF α-ARYLPROPIONIC AND DIARYLACETIC ACIDS
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The cobalt-catalyzed carbonylation of ArCH(R)X (R=CH3, C6H5; X=Cl, Br) in alcoholic solvents under atmospheric pressure of CO is reported.Selective, high yield synthesis of the corresponding acids ArCH(R)COOH can be achieved within a very narrow range of experimental conditions by controlling kinetically the reversible interconversion of intermediate aryl and alkylcobalt complexes.The important roles of the base and of the alcoholic medium are briefly discussed.
- Francalanci, F.,Gardano, A.,Foa, M.
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p. 277 - 282
(2007/10/02)
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