meta- or para-position are highly effective catalysts for the amide condensation reaction in less-polar solvents. In this paper, we report that N-alkyl-4-boronopyridinium halides are more effective catalysts than the previous ones in more polar solvents. N-Alkyl-4-boronopyridinium halides are effective not only for amide condensation between equimolar mixtures of carboxylic acids and amines but also
A CONVENIENT METHOD FOR THE SYNTHESIS OF CARBOXAMIDES AND PEPTIDES BY THE USE OF TETRABUTYLAMMONIUM SALTS
作者:Yutaka Watanabe、Teruaki Mukaiyama
DOI:10.1246/cl.1981.285
日期:1981.3.5
aqueous THF with bis(o-nitrophenyl) phenylphosphonate in the presence of tetrabutylammonium hydrogen sulfate or bromide. Carboxylic esters are also successfully converted to amides via carboxylate salts in one-pot.
N-Alkyl-4-boronopyridinium salts are highly effective and reusable catalysts for the dehydrative amide condensation reaction between equimolar mixtures of carboxylicacids and amines. N-Alkylboronopyridinium salts are thermally stabilized in the order N-alkyl-2-boronopyridinium salt << N-alkyl-3-boronopyridinium salt < N-alkyl-4-boronopyridinium salt. Homogeneous catalysts, such as 4-borono-N-methylpyridinium
Tertiary Amides as Directing Groups for Enantioselective C−H Amination using Ion‐Paired Rhodium Complexes
作者:Kieran J. Paterson、Amit Dahiya、Benjamin D. Williams、Robert J. Phipps
DOI:10.1002/anie.202317489
日期:2024.4.2
Direct amination of benzylic C−H bonds generates important stereocenters. Our approach, in which the chirality of a bimetallic rhodium complex is located on its associated cations, achieves this on tertiary amide-containing substrates to give amination of arylbutyric and arylvaleric acid-derived amides. We believe that the amide most likely interacts directly with the chiral cation to provide a highly