Catalyst‐Free Decarboxylation of Carboxylic Acids and Deoxygenation of Alcohols by Electro‐Induced Radical Formation
作者:Xiaoping Chen、Xiaosheng Luo、Xiao Peng、Jiaojiao Guo、Jiantao Zai、Ping Wang
DOI:10.1002/chem.201905224
日期:2020.3.12
derived from naturally abundant carboxylic acids and alcohols provides a sustainable and inexpensive approach to radical formation via undivided electrochemical cells. The resulting radicals are trapped by an electron-poor olefin or hydrogen atom source to furnish the Giese reaction or reductive decarboxylation products, respectively. A broad range of carboxylic acid (1°, 2°, and 3°) and alcohol (2° and
General and Mild Cobalt-Catalyzed C-Alkylation of Unactivated Amides and Esters with Alcohols
作者:Nicklas Deibl、Rhett Kempe
DOI:10.1021/jacs.6b06448
日期:2016.8.31
The borrowinghydrogen or hydrogen autotransfer methodology is an elegant and sustainable or green concept to construct carbon-carbon bonds. In this concept, alcohols, which can be obtained from barely used and indigestible biomass, such as lignocellulose, are employed as alkylating reagents. An especially challenging alkylation is that of unactivated esters and amides. Only noble metal catalysts based
借用氢或氢自动转移方法是构建碳-碳键的优雅且可持续或绿色的概念。在这个概念中,可以从几乎不使用且难以消化的生物质(例如木质纤维素)中获得的醇被用作烷基化试剂。一个特别具有挑战性的烷基化是未活化的酯和酰胺。仅使用基于铱和钌的贵金属催化剂来完成这些反应。在此,我们报告了醇对未活化酰胺和酯的第一个贱金属催化的 α-烷基化反应。我们实验室最近开发的钳形配体稳定的钴配合物可以非常有效地催化这些反应。预催化剂可以很容易地从市售的起始材料以多克规模合成,并且在碱性反应条件下自活化。这种 Co 催化剂类别还能够介导酯和酰胺的烷基化反应。此外,我们应用该方法合成酮并将醇转化为由两个碳原子拉长的醛。
Sustainable Alkylation of Unactivated Esters and Amides with Alcohols Enabled by Manganese Catalysis
The first example of manganese-catalyzed C-alkylation of the carboxylic acid derivatives is reported. The bench-stable homogeneous manganese complex enables the transformation of the renewable alcohol and carboxylic acid derivative feedstock to higher value esters and amides. The reaction operates via hydrogen autotransfer and ideally produces water as the only side product. Importantly, aliphatic-
α-alkylation of unactivated amides with alcohols is described. Using a NCP-type pincer Ir complex as the precatalyst and KOtBu as the base, the reactions of secondary or tertiary acetamides with benzyl or nonbenzyl primary alcohols occur at 80 °C, furnishing the alkylation products in good yields. This method represents a practical and green means of α-alkylation of amides in a relatively mild, efficient
描述了未活化酰胺与醇的α-烷基化。使用NCP型夹钳Ir络合物作为前催化剂,并使用KO t Bu作为碱,仲或叔乙酰胺与苄基或非苄基伯醇的反应在80°C发生,提供了高收率的烷基化产物。该方法代表了以相对温和,有效和选择性的方式以低催化剂负载量(0.5mol%)进行酰胺的α-烷基化的实用和绿色手段。
Ruthenium hydride/nitrogen tridentate ligand-catalyzed α-alkylation of acetamides with primary alcohols
作者:Takashi Kuwahara、Takahide Fukuyama、Ilhyong Ryu
DOI:10.1039/c3ra42834f
日期:——
The α-alkylation reaction of acetamides with primary alcohols to afford the corresponding amides was accomplished effectively using RuHCl(CO)(PPh3)3 as a catalyst, nitrogen tridentate ligand L1 as an additive, and KOtBu as a base. While the addition of bpy was effective only for benzylic alcohols, L1 affected the alkylation reaction when both benzylic and non-benzylic type alcohols were used.