A catalytic method for the formation of amide bonds was developed in which the amidation of N-hydroxyimino esters with a broad range of amino acid tert-butyl esters is promoted by a niobium catalyst in the absence of solvent. Contrary to the predominant protocol based on reagent control commonly applied to amidation reactions, this study provides insight into an approach based on substrate control
Visible-Light-Mediated Radical Silyl-Oximation of Activated Alkenes Using <i>tert</i>-Butyl Nitrite and Silanes
作者:Stefanie Plöger、Armido Studer
DOI:10.1021/acs.orglett.2c03644
日期:2022.11.25
metal-free radical 1,2-difunctionalization of activated alkenes with various silanes and tert-butyl nitrite is reported. The radical cascade occurs by light-promoted homolytic O–NO bond cleavage of tert-butyl nitrite and subsequent hydrogenatomabstraction by the alkoxyl radicalfrom the silane. Silyl radical addition to the alkene and highly selective cross-coupling of the NO radical with the Si-adduct
报道了用各种硅烷和亚硝酸叔丁酯对活化烯烃进行金属自由基 1,2-双官能化。自由基级联是通过光促进亚硝酸叔丁酯的均裂 O-NO 键断裂以及随后的烷氧基从硅烷中夺取氢原子而发生的。烯烃中的甲硅烷基自由基加成以及 NO 自由基与 Si 加合物 C 自由基的高度选择性交叉偶联以中等至良好的收率提供甲硅烷基肟化产物。该反应具有良好的官能团耐受性,易于放大。
Methyl Pyruvate Oxime as a Carbonyl Synthon: Synthesis of Ureas, Carbamates, Thiocarbamates, and Anilides
作者:Seo Yeon Kim、Hee Nam Lim
DOI:10.1021/acs.orglett.4c01007
日期:2024.5.10
strategy for the synthesis of unsymmetrical ureas, carbamates, thiocarbamates, and anilides was developed with methyl pyruvate oxime as the carbonyl synthon. The intrinsic reactivity of the reagent enabled consecutive disubstitution involving direct amidation and one-pot deoximative substitution with various nucleophiles. The utility of the method was demonstrated with the synthesis of bioactive molecules
Double nucleophilic N-alkylation of alpha-oxime-esters, affording N,N-dialkyl-alpha-amino acids is herein described. Grignard reagents accomplished double N-alkylations via umpolung and various N.N-dialkylated alpha-amino acids were successfully synthesized in 15 min. Both electron-withdrawing sulfonyl groups and electron-donating silyl and methyl groups on oximes were available. Alkylmagnesium species and (E)-configuration of alpha-oxime-ester were essential to this cascade reaction. (C) 2012 Elsevier Ltd. All rights reserved.