based on a photocatalyzed oxidative decarboxylation of oxamic acids is described. The reaction includes in situ generation of an isocyanate from the oxamic acid, using an organic dye as a photocatalyst, a hypervalent iodine reagent as an oxidant and a light source, which trigger the free-radical decarboxylation. This protocol successfully avoids the isolation, purification and storage of carcinogenic
Photocatalyzed decarboxylation of oxamic acids under near-infrared conditions
作者:Ikechukwu Martin Ogbu、Dario M. Bassani、Frédéric Robert、Yannick Landais
DOI:10.1039/d2cc03155h
日期:——
Photocatalyzed oxidative decarboxylation of oxamic acids under near-infrared irradiation using Os(bptpy)2(PF6)2 as catalyst is reported. The reaction was applied to the synthesis of urethanes and heterocyclic amides. Mechanistic studies and comparative penetration depths between the NIR and the visiblelight mediated processes are discussed.
be conducted using a 3-component strategy by simply mixing aldehydes, amines and oxamic acids in the presence of ferrocene, acting both as a photocatalyst under visiblelight and as a Lewis acid. The reaction proceeds through the addition onto the imine of a carbamoyl radical intermediate generated through a charge transfer from the carboxylate ligand to a Fe(III) species (LMCT).
草酸可与亚胺加成,以通常良好的收率提供多种 α-氨基酸酰胺。该过程对于预形成的亚胺是有效的,但也可以使用三组分策略进行,通过在二茂铁存在下简单地混合醛、胺和草酰胺酸,既充当可见光下的光催化剂又充当路易斯酸。该反应通过将氨基甲酰自由基中间体加成到亚胺上来进行,该中间体是通过从羧酸配体到 Fe( III ) 物质 (LMCT) 的电荷转移而产生的。
Silver‐Catalyzed Carbofluorination of Olefins and α‐Fluoroolefins with Carbamoyl Radicals
作者:Émilie Vincent、Julien Brioche
DOI:10.1002/chem.202401419
日期:2024.7.5
A combination of silver oxide (Ag2O) catalyst, potassium persulfate (K2S2O8) and SelectfluorTM was identified to perform radical carbofluorination reactions of olefin and α-fluoroolefin substrates with carbamoyl radicals generated in situ from sodium oxamate salts. Both transformations proceed under mild conditions and provide respectively a straightforward access to β-fluoroamides and β,β-difluoroamides
氧化银 (Ag 2 O) 催化剂、过硫酸钾 (K 2 S 2 O 8 ) 和 Selectflor TM 的组合被确定可利用草酸钠盐原位产生的氨基甲酰基自由基进行烯烃和α-氟烯烃底物的自由基碳氟化反应。两种转化均在温和条件下进行,并分别提供了直接获得β-氟酰胺和β , β-二氟酰胺的途径。