Zirconium catalyzed amide formation without water scavenging
作者:Helena Lundberg、Fredrik Tinnis、Hans Adolfsson
DOI:10.1002/aoc.5062
日期:2019.9
A scalable homogeneous metal‐catalyzed protocol for direct amidation of carboxylic acids is presented. The use of 2–10 mol% of the commercially available Zr(Cp)2(OTf)2·THF results in high yields of amides at moderate temperature, using an operationally convenientreaction protocol that circumvents the use of water scavenging techniques.
lanthanide catalysts showed high catalytic activity and a wide scope of substrates with good to excellent yields under solvent‐freeconditions. Efficient activation of the transamidation can be realized by the above complexes acting as cooperative acid–base bifunctional catalysts, which are proposed to be responsible for the higher reactivity in comparison with simple monometallic catalysts.
carboxylic acid and aminederivatives catalyzed by TiCp2Cl2. Arylacetic acid derivatives reacted with different amines to afford the corresponding amides in good to excellent yield except of aniline. Aryl formic acids failed to react with aniline but smoothly reacted with aliphatic amines and benzylamine in moderate to good yield, fatty acids reacting with benzyl and aliphatic amines give amides in good
Hafnium-Catalyzed Direct Amide Formation at Room Temperature
作者:Helena Lundberg、Hans Adolfsson
DOI:10.1021/acscatal.5b00385
日期:2015.6.5
[Hf(Cp)2Cl2], as catalyst. Amino acids are transformed into their corresponding amides without racemization, and the catalyst displays full selectivity for the amidation of carboxylic acids overesters. Electronic properties of the carboxylic acids were found to have a strong influence on the rate of the amidation reaction, and the need for a balanced amount of molecularsieves was observed to be
Direct Amide Coupling of Non-activated Carboxylic Acids and Amines Catalysed by Zirconium(IV) Chloride
作者:Helena Lundberg、Fredrik Tinnis、Hans Adolfsson
DOI:10.1002/chem.201104055
日期:2012.3.26
Amidst the green: A green, mild and effective protocol for the direct formation of secondary and tertiary amides from non‐activated carboxylicacids and amines in good to excellent yields by employing ZrCl4 as the catalyst is presented (see scheme). The amidecoupling protocol proved to be suitable for scaled up syntheses, and the mild reaction conditions conserve the enantiopurity of chiral starting