This article describes the full details of our reductive approach to nitrones from amides. Reduction of N-siloxyamides with the Schwartz reagent [Cp2ZrHCl], followed by addition of an acid provided functionalized nitrones. The developed conditions were then extended to a catalytic version with the Vaska complex [IrCl(CO)(PPh3)2] and (Me2HSi)2O starting from N-hydroxyamides. 1H NMR studies of the Ir-catalyzed
modern organic synthesis, chemoselectivity is recognized as an important factor in the development of new methodologies. Chemoselective nucleophilic addition to amide carbonyl centers is a challenge because classical methods require harsh reaction conditions to overcome the poor electrophilicity of the amide carbonyl group. We have successfully developed a reductive nucleophilic addition of mild nucleophiles
formation of functionalized nitrones from N-hydroxyamides was reported. The reaction took place through two types of iridium-catalyzed reactions including dehydrosilylation and hydrosilylation. The method showed high chemoselectivity in the presence of sensitive functional groups, such as methyl esters, and was successfully applied to the synthesis of cyclic and macrocyclic nitrones, which are known to be
报道了 Ir 催化从 N-羟基酰胺还原形成官能化硝酮。该反应通过两种类型的铱催化反应进行,包括脱氢硅烷化和氢化硅烷化。该方法在敏感官能团(如甲酯)的存在下显示出高化学选择性,并成功应用于环状和大环硝酮的合成,已知这些化合物很难通过常规方法获得。(1) H NMR 研究强烈支持生成 N-甲硅烷氧基酰胺和 N,O-缩醛作为实际中间体。
Copper‐Catalyzed Electrophilic Amidation of Organotrifluoroborates with Use of
<i>N</i>
‐Methoxyamides
A copper‐catalyzedelectrophilicamidation of aryltrifluoroborates with use of N‐methoxyamides is reported. The reaction shows high functional group compatibility derived from two distinct features: 1) the high stability of the N‐methoxyamides and 2) the nonbasic mild conditions in the presence of LiCl. The developed method can also be applied to the synthesis of enamides, which are widely distributed
据报道,使用N-甲氧基酰胺进行了铜催化的芳基三氟硼酸酯的亲电酰胺化反应。该反应显示出源自两个明显特征的高官能团相容性:1)N-甲氧基酰胺的高稳定性,以及2)在LiCl存在下的非碱性温和条件。所开发的方法还可以用于合成广泛分布于天然产物中的烯酰胺。初步的机理研究表明,第一步是在LiCl的协助下对三氟硼酸芳基酯进行金属转移,生成的芳基铜中间体通过非S N 2氧化添加至N-甲氧基酰胺并随后进行还原消除而提供了苯胺。
Velichko,F.K. et al., Journal of applied chemistry of the USSR, 1965, vol. 38, p. 142 - 147