- Iridium-Catalyzed Asymmetric Hydrogenation of ?- A nd ?-Ketoacids for Enantioselective Synthesis of ?- A nd ?-Lactones
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A highly efficient asymmetric hydrogenation of ?- A nd ?-ketoacids was developed by using a chiral spiro iridium catalyst (S)-1a, affording the optically active ?- A nd ?-hydroxy acids/lactones in high yields with excellent enantioselectivities (up to >99% ee) and turnover numbers (TON up to 100000). This protocol provides an efficient and practical method for enantioselective synthesis of Ezetimibe.
- Hua, Yun-Yu,Bin, Huai-Yu,Wei, Tao,Cheng, Hou-An,Lin, Zu-Peng,Fu, Xing-Feng,Li, Yuan-Qiang,Xie, Jian-Hua,Yan, Pu-Cha,Zhou, Qi-Lin
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supporting information
p. 818 - 822
(2020/02/15)
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- Stereoselective synthesis of 3,4-di-substituted mercaptolactones via photoredox-catalyzed radical addition of thiophenols
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A visible light mediated radical addition of thiophenols on 4-phenylbut-3-enoic acids to give diastereoselective synthesis of 3,4-disubstituted γ-lactones is reported. The reaction precludes the conventional prerequisite of conjugate addition. Furthermore, the lactones were successfully utilized in the synthesis of γ-ketoamides.
- Kouser, Farzana,Sharma, Vijay Kumar,Rizvi, Masood,Sultan, Shaista,Chalotra, Neha,Gupta, Vivek K.,Nandi, Utpal,Shah, Bhahwal Ali
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p. 2161 - 2166
(2018/05/05)
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- Visible-Light-Promoted Synthesis of 1,4-Dicarbonyl Compounds via Conjugate Addition of Aroyl Chlorides
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A facile visible-light photocatalytic conjugate addition to prepare 1,4-dicarbonyl compounds has been developed by employing readily available aroyl chlorides as aryl radical sources. This operationally simple method shows a broad scope with regard to both aroyl chlorides and Michael acceptors. As a result, a variety of 1,4-diketones were efficiently synthesized in moderate to good yields.
- Wang, Chao-Ming,Song, Dan,Xia, Peng-Ju,Wang, Jing,Xiang, Hao-Yue,Yang, Hua
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supporting information
p. 271 - 274
(2018/01/27)
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- Decarboxylative 1,4-Addition of α-Oxocarboxylic Acids with Michael Acceptors Enabled by Photoredox Catalysis
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Enabled by iridium photoredox catalysis, 2-oxo-2-(hetero)arylacetic acids were decarboxylatively added to various Michael acceptors including α,β-unsaturated ester, ketone, amide, aldehyde, nitrile, and sulfone at room temperature. The reaction presents a new type of acyl Michael addition using stable and easily accessible carboxylic acid to formally generate acyl anion through photoredox-catalyzed radical decarboxylation.
- Wang, Guang-Zu,Shang, Rui,Cheng, Wan-Min,Fu, Yao
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supporting information
p. 4830 - 4833
(2015/10/12)
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- Enantioselective Ruthenium(II)/Xyl-SunPhos/Daipen-Catalyzed hydrogenation of γ-Ketoamides
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A0series of γ-hydroxy amides were synthesized with high ena~tioselectivities (up to 99%) usyng asymmetric hydrogenation of the corresponding γ-ketoamides in the presence of Ru-Xyl-SunPhos-Daipen catalyst providing key building blocks for a variety of natu
- Zhao, Mengmeng,Li, Wanfang,Li, Xiaoming,Ren, Kai,Tao, Xiaoming,Xie, Xiaomin,Ayad, Tahar,Ratovelomanana-Vidal, Virginie,Zhang, Zhaowuo
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p. 6164 - 6171
(2014/07/21)
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- Direct amide formation from unactivated carboxylic acids and amines
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The direct coupling of unactivated carboxylic acids with amines can be performed in toluene 110 °C in the absence of catalyst. The use of simple zirconium catalysts at 5 mol% loading gave amide formation in as little as 4 h.
- Allen, C. Liana,Chhatwal, A. Rosie,Williams, Jonathan M. J.
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supporting information; experimental part
p. 666 - 668
(2012/01/13)
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- Carbamoylimidazolium and thiocarbamoylimidazolium salts: Novel reagents for the synthesis of ureas, thioureas, carbamates, thiocarbamates and amides
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Carbamoylimidazolium salts act as efficient N,N-disubstituted carbamoylating reagents. These salts are readily prepared by the sequential treatment of secondary amines with N,N′-carbonyldiimidazole (CDI) and iodomethane. The carbamoylimidazolium salts are more efficient carbamoyl transfer reagents than the intermediate carbamoylimidazoles, as a result of the 'imidazolium' effect. Kinetic studies on the base promoted hydrolysis of both carbamoylimidazoles and carbamoylimidazolium salts reveal over a hundred-fold rate acceleration. The salts react with amines, thiols, phenols/alcohols, and carboxylic acids in high yields, without the need for subsequent chromatographic purification of the products, producing ureas, thiocarbamates, carbamates, and amides, respectively. Analogous thiocarbamoylimidazolium salts were also synthesized from secondary amines and N,N′-thiocarbonyldiimidazole (TCDI), followed by methylation with iodomethane.
- Grzyb, Justyna A.,Shen, Ming,Yoshina-Ishii, Chiaki,Chi,Brown, R. Stanley,Batey, Robert A.
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p. 7153 - 7175
(2007/10/03)
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- Carbamoylimidazolium salts as diversification reagents: An application to the synthesis of tertiary amides from carboxylic acids
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An efficient method for the preparation of tertiary amides from carbamoylimidazolium salts and carboxylic acids is described. The transformation occurs at room temperature and under relatively mild conditions. The carbamoylimidazolium salts are obtained from the reaction of secondary amines with N,N′-carbonyldiimidazole, followed by methylation with methyl iodide. The utility of this reaction was demonstrated in the formation of Weinreb amides and in a short synthesis of fused bicyclic amides. The introduction of this reaction now permits carbamoylimidazolium salts to be utilized in the formation of tertiary amides, ureas, carbamates and thiocarbamates under a single set of conditions.
- Grzyb, Justyna A.,Batey, Robert A.
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p. 7485 - 7488
(2007/10/03)
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- 6-Phenyl-6-alkylamido-5,6-dihydro-2H-pyran-2-ones: Novel HIV protease inhibitors
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Publications from our laboratories have recently described a series of 3-thioaryl substituted-4-hydroxy-pyrones as HIV protease inhibitors. The current work examines the analogues 5,6-dihydro-2H-pyran-2-ones with 6,6-substitutions focusing on the use of 1
- Hamilton, Harriet W.,Tait, Bradley D.,Gajda, Christopher,Hagen, Susan E.,Ferguson, Donna,Lunney, Elizabeth A.,Pavlovsky, Alexander,Tummino, Peter J.
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p. 719 - 724
(2007/10/03)
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- A Novel Aromatic Electrophilic Substitution: Acylation of Aromatics with Cyclic Isoimidium Salts to Yield N,N-Disubstituted β-Aroylcarboxamides
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Cyclic isoimidium perchlorates derived from N,N-diethylphthalamic acid and the monomorpholides of succinic and maleic acid react with benzene, toluene or anisole in the presence of aluminium chloride to give the corresponding β-aroylcarboxamides in modera
- Balaban, Alexandru R.,Balaban, Theodor-Silviu,Boyd, Gerhard V.
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p. 577 - 578
(2007/10/02)
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- N,N-Dialkylamides of 2-Hydroxy-2-phenyl-cyclopropan-1-carboxylic Acid - Photochemical Synthesis and Determination of the Structure
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Irradiation of N,N-dialkylamides of β-benzoylpropionic acid 2a, b in ether by n,?*-excitation leads to the corresponding amides of the hitherto unknown 2-hydroxy-2-phenyl-cyclopropancarboxylic acid 3a, b, 4a, b.The photocyclization yields diast
- Henning, H.-G.,Berlinghoff, R.,Mahlow, A.,Koeppel, H.,Schleinitz, K.-D.
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p. 914 - 918
(2007/10/02)
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