取代脲有许多应用,但它们的合成通常需要使用剧毒的起始材料。在此,我们描述了第一种通过甲醇与伯胺脱氢偶联选择性合成对称脲的贱金属催化剂。使用钳形负载铁催化剂,生成了一系列尿素,分离产率高达 80%(相当于催化转化率高达 160),且 H 2为唯一副产物。机理研究表明,从甲醇脱氢开始逐步生成甲醛,甲醛被胺捕获,生成甲酰胺。然后甲酰胺脱氢产生暂时的异氰酸酯,其与另一当量的胺反应形成脲。这些机理见解使得铁催化方法得以开发,用于从酰胺和胺合成不对称脲。
Polynuclear Gold [Au<sup>I</sup>
]<sub>4</sub>
, [Au<sup>I</sup>
]<sub>8</sub>
, and Bimetallic [Au<sup>I</sup>
<sub>4</sub>
Ag<sup>I</sup>
] Complexes: C−H Functionalization of Carbonyl Compounds and Homogeneous Carbonylation of Amines
作者:Ekaterina S. Smirnova、José M. Muñoz Molina、Alice Johnson、Nuno A. G. Bandeira、Carles Bo、Antonio M. Echavarren
DOI:10.1002/anie.201603200
日期:2016.6.20
tetranuclear gold complexes, a structurally unprecedented octanuclear complex with a planar [Au(I) 8 ] core, and pentanuclear [Au(I) 4 M(I) ] (M=Cu, Ag) complexes is presented. The linear [Au(I) 4 ] complex undergoes C-H functionalization of carbonyl compounds under mild reaction conditions. In addition, [Au(I) 4 Ag(I) ] catalyzes the carbonylation of primary amines to form ureas under homogeneous conditions
Carbondioxide is regarded as a reliable C1 building block in organic synthesis because of the nontoxic, abundant, and economical characteristics of carbondioxide. In this manuscript, a commercially available oxovanadium(V) compound was demonstrated to serve as an efficientcatalyst for the catalytic amination of carbondioxide under ambientpressure in the synthesis of ureas. The catalytic transformation
由于二氧化碳无毒、丰富、经济的特点,二氧化碳被认为是有机合成中可靠的C1结构单元。在这份手稿中,一种市售的氧钒 ( V ) 化合物被证明可作为一种有效的催化剂,用于在环境压力下合成尿素中的二氧化碳催化胺化。还进行了手性胺催化转化为相应的手性脲而不丧失手性。此外,在环境压力下成功实现了克级催化尿素合成,以验证这种二氧化碳催化活化的可扩展性。
Direct extraction of carbonyl from waste polycarbonate with amines under environmentally friendly conditions: scope of waste polycarbonate as a carbonylating agent in organic synthesis
作者:Sukhdeep Singh、Yong Lei、Andreas Schober
DOI:10.1039/c4ra14319a
日期:——
An efficient green method for converting polycarbonate into urea derivatives and bisphenol-A by sequestration of carbonyl from waste polycarbonate.
一种高效的绿色方法,通过从废旧聚碳酸酯中捕获羰基,将其转化为脲衍生物和双酚A。
[EN] METHOD FOR CATALYTICALLY ACTIVATING CARBON DIOXIDE AS CARBONYLATION REAGENT WITH INORGANIC SULFUR<br/>[FR] PROCÉDÉ POUR L'ACTIVATION CATALYTIQUE DE DIOXYDE DE CARBONE EN TANT QUE RÉACTIF DE CARBONYLATION AVEC DU SOUFRE INORGANIQUE<br/>[ZH] 无机硫催化活化二氧化碳作为羰基化试剂的方法
Fast cobalt carbonyl-mediated generation of ureas from primary amines was performed using high-density microwave irradiation. This enhanced method permitted the preparation of symmetrical ureas in good yields and unsymmetrical ureas in moderate yields. The reaction times varied between 10 s and 40 min. The proposed mechanisin for the reaction includes in situ generation of an intermediate isocyanate that subsequently traps the free amine, producing the urea product. (c) 2005 Elsevier Ltd. All rights reserved.