A CO<sub>2</sub>-Catalyzed Transamidation Reaction
作者:Yang Yang、Jian Liu、Fadhil S. Kamounah、Gianluca Ciancaleoni、Ji-Woong Lee
DOI:10.1021/acs.joc.1c02077
日期:2021.12.3
Transamidation reactions are often mediated by reactive substrates in the presence of overstoichiometric activating reagents and/or transition metal catalysts. Here we report the use of CO2 as a traceless catalyst: in the presence of catalytic amounts of CO2, transamidation reactions were accelerated with primary, secondary, and tertiary amide donors. Various amine nucleophiles including amino acid
在过量化学计量的活化试剂和/或过渡金属催化剂的存在下,转酰胺基反应通常由反应性底物介导。在这里,我们报告了使用 CO 2作为无痕催化剂:在催化量的 CO 2存在下,使用伯、仲和叔酰胺供体加速转酰胺反应。包括氨基酸衍生物在内的各种胺类亲核试剂都被耐受,这表明转酰胺基在肽修饰和聚合物降解中的实用性(例如,Nylon-6,6)。特别是,N , O -二甲基羟基酰胺(Weinreb 酰胺)在 CO 2催化的转酰胺基反应中与 N 2相比表现出明显的反应性大气层。进行了比较 Hammett 研究和动力学分析,以阐明分子 CO 2的催化活化机制,这得到了 DFT 计算的支持。我们将CO 2在转酰胺基反应中的积极作用归因于通过与亲电子CO 2共价结合来稳定四面体中间体。
Direct Acyl Substitution of Carboxylic Acids: A Chemoselective O- to N-Acyl Migration in the Traceless Staudinger Ligation
作者:Andrew D. Kosal、Erin E. Wilson、Brandon L. Ashfeld
DOI:10.1002/chem.201201773
日期:2012.11.5
chlorophosphite‐modified, Staudinger‐like acylation of azides involving a highly chemoselective, direct nucleophilic acyl substitution of carboxylicacids is described. The reaction provides the corresponding amides with analytical purity in 32–97 % yield after a simple aqueous workup without the need for a pre‐activation step. The use of chlorophosphites as dual carboxylic acid–azide activating agents
Direct Synthesis of Amides from Carboxylic Acids and Amines Using B(OCH<sub>2</sub>CF<sub>3</sub>)<sub>3</sub>
作者:Rachel M. Lanigan、Pavel Starkov、Tom D. Sheppard
DOI:10.1021/jo400509n
日期:2013.5.3
range of amines. In most cases, the amide products can be purified by a simple filtration procedure using commercially available resins, with no need for aqueous workup or chromatography. The amidation of N-protected amino acids with both primary and secondary amines proceeds effectively, with very low levels of racemization. B(OCH2CF3)3 can also be used for the formylation of a range of amines in good
C2 symmetrical nickel complexes derived from α-amino amides as efficient catalysts for the enantioselective addition of dialkylzinc reagents to aldehydes
作者:Jorge Escorihuela、Belen Altava、M. Isabel Burguete、Santiago V. Luis
DOI:10.1016/j.tet.2012.11.025
日期:2013.1
amides were studied for the enantioselectiveaddition of dialkylzincreagents to aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Through optimization of structure and reaction conditions, the best ligand provided secondary alcohols in excellent yields (up to 98%) and enantioselectivity of up to 99% ee for (R)-enantiomer
作者:José G. Hernández、Karen J. Ardila-Fierro、Deborah Crawford、Stuart L. James、Carsten Bolm
DOI:10.1039/c7gc00615b
日期:——
Mechanochemical chemoenzymatic peptide and amidebondformation catalysed by papain was studied by ball milling. Despite the high-energy mixing experienced inside the ball mill, the biocatalyst proved stable and highly efficient to catalyse the formation of α,α- and α,β-dipeptides. This strategy was further extended to the enzymatic acylation of amines by milling, and to the mechanosynthesis of a derivative