- Regio- And Stereoselective Synthesis of Diverse 3,4-Dihydro-2-quinolones through Catalytic Hydrative Cyclization of Imine- And Carbonyl-Ynamides with Water
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Transition-metal-catalyzed alkyne hydration reaction has attracted considerable interest in the past decades because this approach would lead to the facile and efficient formation of synthetically useful carbonyls. However, transition-metal-catalyzed alky
- Zhu, Bo-Han,Zhang, Ying-Qi,Xu, Hao-Jin,Li, Long,Deng, Guo-Cheng,Qian, Peng-Cheng,Deng, Chao,Ye, Long-Wu
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- Discovery of Oxygen α-Nucleophilic Addition to α,β-Unsaturated Amides Catalyzed by Redox-Neutral Organic Photoreductant
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The conjugate additions of oxygen-centered nucleophiles to conjugate acceptors are among the most powerful C-O bond formation reactions. The conjugate addition normally takes place at the β-position carbon to the electron-withdrawing group, resulting in the formation of a stabilized carbanion intermediate that can be quenched by proton or electrophiles to form the β-addition (i.e., hetero-Michael addition) products. On the contrary, the formation of α-hydroxyl or alkoxyl amides through conjugate addition needs an α,β-inverse addition. Nevertheless, a regio-inversed nucleophilic α-addition of oxygen-centered nucleophiles to α,β-unsaturated carbonyl compounds still remains less explored because of the electronic mismatch. In this research, we discovered the first α-specific nucleophilic addition of α,β-unsaturated amides with oxygen and fluoride nucleophiles. This region-inversed nucleophilic addition is enabled by the catalysis of a novel redox-neutral nondonor-acceptor organic photoreductant (CBZ6). As low as 0.5 mol % of visible light photoreductant was employed. The mechanistic insights were also explored. The oxidative potential of the excited state of CBZ6 is obtained in -1.92 V (vs SCE), presenting a stronger reductive potential than representative metal-cored or organic photoredox catalysts. This feature enabled the umpolung of α,β-unsaturated amides to take place α-nucleophilic addition other than the normal β-addition.
- Luan, Zi-Hong,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 20942 - 20947
(2020/12/22)
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- Multicomponent multicatalyst reactions (MC)2R: One-pot synthesis of 3,4-dihydroquinolinones
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A Rh/Pd/Cu catalyst system led to an efficient synthesis of dihydroquinolinones in one-pot, two operations. The reaction features the first triple metal-catalyzed transformations in one reaction vessel, without any intermediate workup. The conjugate-addition/amidation/amidation reaction sequence is highly modular, divergent, and practical.
- Zhang, Lei,Sonaglia, Lorenzo,Stacey, Jason,Lautens, Mark
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supporting information
p. 2128 - 2131
(2013/06/05)
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- Substituent position-driven reaction pathways in the heterogeneous one-pot reduction/asymmetric hydrogenation of nitro-substituted (E)-2,3- diphenylpropenoic acids over Pd catalyst
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The reaction pathway in the heterogeneous enantioselective hydrogenation of nitro-substituted (E)-2,3-diphenylpropenoic acids over Pd catalyst modified by cinchonidine is determined by the position of the substituent. The reaction route was indicated by the H2 consumption curve and enantioselectivity of the final amino acid or 3-phenyl-1,2,3,4-tetrahydro-2- quinolone formed by intramolecular amidation. The obtained enantioselectivities were low with the exception of acids bearing nitro substituent in para position on the 3-phenyl moiety, the latter resulting in good, up to 80 % optical purity. The present study is the first to report the enantioselective heterogeneous catalytic preparation of 1,2,3,4-tetrahydro-2-quinolones and presents an attractive method for obtaining optically enriched 3-(4-aminophenyl)-2- phenylpropionic acids. ARKAT-USA, Inc.
- Szoelloesi, Gyoergy,Bartok, Mihaly
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- Preparation of 2-Quinolones by sequential heck reduction-cyclization (HRC) reactions by using a multitask palladium catalyst
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One-pot sequential Heck reduction-cyclization (HRC) reactions leading to the synthesis of substituted 2-quinolones have been developed by using a heterogeneous or mixed homogeneous/heterogeneous multitask palladium catalyst with charcoal as a support. The whole sequence occurs under very mild conditions without the need for additives (ligand or base) by taking advantage of the high reactivity of aryldiazonium salts as "super electrophiles". Recycling experiments showed that the reused heterogeneous Pd°/C catalyst was not able to promote another HRC sequence but was, however, still highly active for hydrogenation, hydrodehalogenation, as well as hydrogenolysis reactions.
- Felpin, Francois-Xavier,Coste, Jerome,Zakri, Cecile,Fouquet, Eric
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experimental part
p. 7238 - 7245
(2010/03/25)
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- The tandem reaction combining radical and ionic processes: an efficient approach to substituted 3,4-dihydroquinolin-2-ones
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3,4-Dihydroquinolin-2-ones are of great importance in the areas of pharmaceuticals. However, the direct intramolecular radical cyclizations of the corresponding amide compounds favor 5-exo products 2. Reports on the radical cyclization reactions producing
- Zhou, Wang,Zhang, Liangren,Jiao, Ning
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experimental part
p. 1982 - 1987
(2009/08/07)
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- Regioselective palladium(II)-catalyzed synthesis of five- or seven-membered ring lactones and five-, six- or seven-membered ring lactams by cyclocarbonylation methodology
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2-Allylphenols react with carbon monoxide and hydrogen in the presence of catalytic quantities of a cationic palladium(II) complex [(PCy3)2Pd(H)(H2O)]+BF4- or palladium acetate and 1,4-bis(diphenylpho
- El Ali, Bassam,Okuro, Kazumi,Vasapollo, Giuseppe,Alper, Howard
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p. 4264 - 4270
(2007/10/03)
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