- Dual H-bond activation of NHC-Au(i)-Cl complexes with amide functionalized side-arms assisted by H-bond donor substrates or acid additives
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Novel approach with amide-tethered H-bond donor NHC ligands enabled Au(i)-catalysis via H-bonding. The plain NHC-Au(i)-Cl complex catalysed conversions of terminal N-propynamides to oxazolines, and enyne cycloisomerization with an acid additive, in DCM at
- Sepp?nen, Otto,Aikonen, Santeri,Muuronen, Mikko,Alamillo-Ferrer, Carla,Burés, Jordi,Helaja, Juho
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supporting information
p. 14697 - 14700
(2020/12/02)
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- Synthesis of 2,2,2-Trifluoroethyl Oxazoles, Oxazolines and Furans via Alkyne Oxytrifluoromethylation
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This study reports an oxytrifluoromethylation method for construction of oxazoles and furans motif and the concurrent incorporation of a 2,2,2-trifluoroethyl group at the aromatic C5-position. High-valent copper(III) trifluoromethyl compounds are crucial
- Dong, Jia-Jia,Zhang, Song-Lin
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supporting information
p. 795 - 800
(2020/01/24)
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- Gold-Catalyzed Stereoselective Domino Cyclization/Alkynylation of N-Propargylcarboxamides with Benziodoxole Reagents for the Synthesis of Alkynyloxazolines
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A concise and highly stereoselective synthesis of alkynyloxazolines via a gold-catalyzed domino cyclization-alkynylation cascade of N-propargylcarboxamides with benziodoxole reagents is reported. This new protocol, which represents an attractive alternati
- Zhao, Ximei,Tian, Bing,Yang, Yangyang,Si, Xiaojia,Mulks, Florian F.,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 3155 - 3162
(2019/05/10)
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- Palladium-Catalyzed Cascade Difluoroalkylation/Cyclization of N-Propargylamides: Synthesis of Oxazoles and Oxazolines
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A palladium-catalyzed process to construct oxazoles and oxazolines with broad functional-group tolerance has been developed, and the method introduces difluoromethyl groups into heterocycles in a one-pot fashion. This system uses a carbonyl oxygen as the acceptor for the addition of a vinylpalladium intermediate to achieve the cyclization. Oxazoline derivatives are generated as the Z-isomer with high stereoselectivity. Additionally, we validated the tentative mechanism of this reaction.
- Ma, Jun-Wei,Wang, Qiang,Wang, Xin-Gang,Liang, Yong-Min
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p. 13296 - 13307
(2018/11/02)
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- Sulfur–Fluoride Exchange (SuFEx)-Mediated Synthesis of Sterically Hindered and Electron-Deficient Secondary and Tertiary Amides via Acyl Fluoride Intermediates
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Amide bond formation is one of the most executed reactions in chemistry and biology. This is largely due to the ubiquity of the amide functional group in biological molecules, natural products and pharmaceutically important drugs. We report here the development of “SuFExAmide”: a new sulfur–fluoride exchange (SuFEx) click chemistry based protocol for the efficient amidation of carboxylic acids via acyl fluoride intermediates. We have developed benzene-1,3-disulfonyl fluoride as a cost effective, powerful and versatile coupling agent, which delivers challenging secondary and tertiary amides in excellent yields from sterically hindered and electron-deficient amines. The straightforward method offers significant benefits over existing protocols in terms of substrate scope, efficiency and ease of operation and is demonstrated by the synthesis of 44 amides, including GNF6702, an antiprotozoal drug candidate. In the majority of cases, the amide products are obtained in high yield without the need for excess reagents or chromatographic purification.
- Smedley, Christopher J.,Barrow, Andrew S.,Spiteri, Christian,Giel, Marie-Claire,Sharma, Pallavi,Moses, John E.
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supporting information
p. 9990 - 9995
(2017/08/01)
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- Facile expeditious one-pot synthesis and antifungal evaluation of disubstituted 1,2,3-triazole with two amide linkages
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A library of twenty five amide linked 1,4-disubstituted 1,2,3-triazoles have been prepared through a facile expeditious synthetic protocol involving Cu(I) mediated cyclization of N-(2-methylbut-3-yn-2-yl)aromatic amides and in situ generated 2-azido-N-substituted propanamides. Structures of newly synthesized compounds (5a–5y) were confirmed by analytical techniques, such as FTIR, 1H NMR, 13C NMR, and HRMS. In vitro antifungal activity was also examined against two fungal strains Candida albicans and Aspergillus niger by serial dilution method. The compounds 5 m and 5w exhibited appreciable potent activity.
- Kaushik,Luxmi, Raj
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supporting information
p. 2225 - 2231
(2017/11/15)
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- Ruthenium-Catalyzed Hydroalkynylative Cyclization of 1,6-Enynes Induced by Substituent Effects
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The ruthenium-catalyzed 1,6-enyne cyclization in the presence of bulky substituted terminal alkyne proceeds smoothly at room temperature to afford highly substituted five-membered cyclic compounds featuring a 1,5-enyne motif. Deuterium-labeling experiment
- Liu, Rui,Ni, Zhenjie,Giordano, Laurent,Tenaglia, Alphonse
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supporting information
p. 4040 - 4043
(2016/08/30)
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- Silver-Catalyzed Cyclization of Propargylic Amides to Oxazolines
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A ligand-accelerated effect is observed in the cyclization of propargylic amides catalyzed by bis(pyridyl)silver(I) complexes, with an unexpected reversal of electronic demand to the analogous NH addition reaction. The catalyst was found to be effective for internal alkyne substrates, offering exclusive selectivity for the 5-exo-dig product. Differences in selectivity profile between gold- and silver-catalyzed processes are highlighted and discussed.
- Wong, Valerie H. L.,White, Andrew J. P.,Hor,Hii
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supporting information
p. 3943 - 3948
(2016/01/25)
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- Cu(I)-catalyzed synthesis of dihydropyrimidin-4-ones toward the preparation of β- And β3-amino acid analogues
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A copper(I)-catalyzed synthesis of substituted dihydropyrimidin-4-ones from propargyl amides via the formation of ketenimine intermediate has been successfully developed; the synthesis afforded good isolated yields (80-95%). The mild reaction conditions at room temperature allow the reaction to proceed to completion in a few hours without altering the stereochemistry. Further, by involving a variety of reactive nucleophiles, the obtained substituted dihydropyrimidin-4-ones were elegantly transformed into the corresponding β- and β3-amino acid analogues.
- Rajagopal, Basker,Chen, Ying-Yu,Chen, Chun-Chi,Liu, Xuan-Yu,Wang, Huei-Ren,Lin, Po-Chiao
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p. 1254 - 1264
(2014/03/21)
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- CuI-catalyzed cycloisomerization of propargyl amides
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The synthesis of substituted dihydrooxazoles by the CuI-catalyzed cycloisomerization of terminal propargyl amides is reported. The reaction has been shown to have good substrate scope and experiments to delineate the mechanism have been performed. Substrates containing a benzylic methylene were oxidized to the ketone under the reaction conditions.
- Alhalib, Ali,Moran, Wesley J.
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p. 795 - 800
(2014/01/23)
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- Facile, selective, and regiocontrolled synthesis of oxazolines and oxazoles mediated by ZnI2 and FeCl3
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An expedient method for a direct approach to the selective and regiocontrolled synthesis of 2-oxazolines and 2-oxazoles mediated by ZnI 2 and FeCl3 is described. A Lewis acid promoted cyclization of acetylenic amide with various func
- Senadi, Gopal Chandru,Hu, Wan-Ping,Hsiao, Jia-Shing,Vandavasi, Jaya Kishore,Chen, Chung-Yu,Wang, Jeh-Jeng
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supporting information
p. 4478 - 4481
(2012/10/30)
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- Tungsten and molybdenum catalyst-mediated cyclisation of N-propargyl amides
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Tungsten and molybdenum catalysts were employed to promote the cyclisation of N-propargylic amides to afford the corresponding oxazolines or oxazines via 5-exo-dig or 6-endo-dig mode.
- Meng, Xiangjian,Kim, Sunggak
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supporting information; experimental part
p. 4429 - 4431
(2011/07/29)
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- Cyclization-carbonylation-cyclization coupling reactions of propargyl acetates and amides with palladium(II)-bisoxazoline catalysts
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Clever boxing: A cyclization-carbonylation-cyclization-coupling reaction of propargyl acetates 1 or amides 2 in the presence of a palladium(II)- bisoxazoline (box) catalyst afforded symmetrical ketones of types 3 and 4, respectively, containing two heterocyclic groups in moderate to excellent yields (see scheme; tfa=trifluoroacetate). Compounds 3 were converted into ketones containing two 3(2H)-furanone rings.
- Yasuhara, Sumie,Sasa, Makiko,Kusakabe, Taichi,Takayama, Hiroyuki,Kimura, Masayuki,Mochida, Tomoyuki,Kato, Keisuke
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supporting information; experimental part
p. 3912 - 3915
(2011/06/20)
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- Silver-catalyzed preparation of oxazolines from N-propargylamides
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Treatment of N-propargylamides with 5 mol% of silver hexafluoroantimonate results in the rapid formation of oxazolines in essentially quantitative yield. Georg Thieme Verlag Stuttgart.
- Harmata, Michael,Huang, Chaofeng
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scheme or table
p. 1399 - 1401
(2009/04/06)
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- Efficient and general synthesis of 5-(alkoxycarbonyl)methylene-3-oxazolines by palladium-catalyzed oxidative carbonylation of prop-2-ynylamides
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A variety of prop-2-ynylamides have been carbonylated under oxidative conditions to give oxazolines, oxazolines with chelating groups, and bisoxazolines bearing an (alkoxycarbonyl)methylene chain at the 5 position in good yields. The cyclization-alkoxycarbonylation process was carried out in alcoholic media at 50-70°C and under 24 bar pressure of 3:1 carbon monoxide/air in the presence of catalytic amounts of 10% Pd/C or PdI2 in conjunction with KI. Cyclization occurred by anti attack of an oxygen function on the palladium-coordinated triple bond, followed by stereospecific alkoxycarbonylation, strictly resulting in E-stereochemistry. The structures of representative oxazolines and bisoxazolines have been determined by X-ray diffraction analysis.
- Bacchi, Alessia,Costa, Mirco,Gabriele, Bartolo,Pelizzi, Giancarlo,Salerno, Giuseppe
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p. 4450 - 4457
(2007/10/03)
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