- Solvent- and transition metal-free amide synthesis from phenyl esters and aryl amines
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A general, economical, and environmentally friendly method of amide synthesis from phenyl esters and aryl amines was developed. This new method has significant advantages compared to previously reported palladium-catalyzed approaches. The reaction is performed transition metal- and solvent-free, using a cheap and environmentally benign base, NaH. This approach enabled us to obtain target amides in high yields with high atom economy.
- Rzhevskiy, Sergey A.,Ageshina, Alexandra A.,Chesnokov, Gleb A.,Gribanov, Pavel S.,Topchiy, Maxim A.,Nechaev, Mikhail S.,Asachenko, Andrey F.
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Read Online
- On DABAL-Me3 promoted formation of amides
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The range and utility of DABAL-Me3 couplings of methyl esters and free carboxylic acids with primary and secondary amines under a variety of conditions (reflux, sealed tube, microwave) has been compared for a significant range of coupling partners of relevance to the preparation of amides of interest in pharmaceutical chemistry. Commercial microwave reactors promote the fastest couplings and allow the use of significantly sterically hindered amines (primary and secondary) and carboxylic acids derivatives. The influence of microwave energy on the reaction system was shown to be typically related to thermal effects (over-pressuring and superheating).
- Dubois, Nathalie,Glynn, Daniel,McInally, Thomas,Rhodes, Barrie,Woodward, Simon,Irvine, Derek J.,Dodds, Chris
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supporting information
p. 9890 - 9897
(2013/10/22)
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- Investigation of ligand steric effects on a highly cis-selective Rh(i) cyclopropanation catalyst
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Four new Rh(i) complexes bearing chelating imine-functionalized N-heterocyclic carbene ligands have been synthesized and characterized. The catalytic activity of these new Rh(i) complexes has been tested in the cyclopropanation reaction between ethyl diazoacetate and styrene. One of the new complexes, having ethyl groups on the ligand N-aryl ring, exhibited a reactivity and a cis-diastereoselectivity that were comparable to our previously reported Rh(i) cyclopropanation catalyst of this type, and a higher yield and cis-diastereoselectivity were obtained at lower catalyst loadings and higher temperatures. The other new Rh(i) complexes were found to be inferior to the previously reported Rh(i) cyclopropanation catalyst. The catalytic study gave important information about the effect that changing the steric requirements of the substituents at the ligand system has on the efficiency and cis-diastereoselectivity of the complexes as cyclopropanation catalysts.
- Rosenberg, Marianne Lenes,Langseth, Eirin,Krivokapic, Alexander,Gupta, Nalinava Sen,Tilset, Mats
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scheme or table
p. 2306 - 2313
(2011/12/03)
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- Cyclopentadienyl-free rare-earth metal amides [{(CH2SiMe 2){(2,6iPr2C6H3)N} 2}Ln{N(SiMe3)2}(THF)] as highly efficient versatile catalysts for C-C and C-N bond formation
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Efficient methods have been developed for the direct synthesis of amides from aldehydes and a straightforward route to propiolamidines using cyclopentadienyl-free rare-earth metal amides [{(CH2SiMe 2){(2,6-iPr2C6H3)N} 2}Ln{N(SiMe3)2}(THF)] [Ln = Yb (1), Y (2), Dy (3), Sm (4), Nd (5)] as versatile catalysts, The results indicate that in the direct synthesis of amides from aldehydes the catalysts have the activity order 2>1~3~4~5. These methods have the advantage of easy preparation of the catalysts, low catalyst loading, high conversion of substrates to products, mild reaction conditions, and compatibility with a wide range of substrates.
- Wu, Yunjun,Wang, Shaowu,Zhang, Lijun,Yang, Gaosheng,Zhu, Xiancui,Zhou, Zhihong,Zhu, Hong,Wu, Shihong
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supporting information; experimental part
p. 326 - 332
(2010/04/06)
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