Metal free chemoselective reduction of α-keto amides using TBAF as catalyst
作者:N. Chary Mamillapalli、Govindasamy Sekar
DOI:10.1039/c4ra13090a
日期:——
metal and ligand free chemoselective reduction of the keto group and complete reduction of the both keto and amide groups of α-keto amide with hydrosilanes using tetrabutylammoniumflouride (TBAF) as catalyst have been accomplished. This methodology affords an efficient and economic route for the synthesis of biologically important α-hydroxyamides and β-amino alcohols. The other important advantage of
An efficient and practical method was developed for the synthesis of tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones based on the decarboxylative cyclization reaction of α-ketoamides and proline. In most cases, tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones were obtained with perfect diastereoselectivity to give trans-isomer in excellent yield.
基于α-酮酰胺与脯氨酸的脱羧环化反应,开发了一种高效,实用的四氢-1 H-吡咯并[1,2 - a ]咪唑-2-酮的合成方法。在大多数情况下,以完美的非对映选择性获得四氢-1 H-吡咯并[1,2- a ]咪唑-2-酮,从而以优异的收率得到反式异构体。
Enantioselective Synthesis of α-Hydroxy Amides and β-Amino Alcohols from α-Keto Amides
作者:N. Chary Mamillapalli、Govindasamy Sekar
DOI:10.1002/chem.201503569
日期:2015.12.14
Synthesis of enantiomerically enriched α‐hydroxy amides and β‐amino alcohols has been accomplished by enantioselective reduction of α‐keto amides with hydrosilanes. A series of α‐keto amides were reduced in the presence of chiral CuII/(S)‐DTBM‐SEGPHOS catalyst to give the corresponding optically active α‐hydroxy amides with excellent enantioselectivities by using (EtO)3SiH as a reducing agent. Furthermore
对映体富集的α-羟基酰胺和β-氨基醇的合成已通过用氢硅烷将α-酮酰胺对映选择性还原而完成。通过使用(EtO)3 SiH作为还原剂,在手性Cu II /(S)-DTBM-SEGPHOS催化剂存在下还原了一系列α-酮酰胺,得到了具有出色对映选择性的相应光学活性α-羟基酰胺。此外,使用相同的手性铜催化剂,然后在(EtO)3 SiH存在下,用四正丁基氟化铵(TBAF)催化剂,一锅完全还原了α-酮酰胺的酮基和酰胺基。相应的手性β-氨基醇衍生物。
Friedel–Crafts Hydroxyalkylation of Indoles with α-Keto Amides using Reusable K<sub>3</sub>PO<sub>4</sub>/<i>n</i>Bu<sub>4</sub>NBr Catalytic System in Water
作者:Alagesan Muthukumar、Govindasamy Sekar
DOI:10.1021/acs.joc.8b00844
日期:2018.8.17
in water as solvent through a solid–liquid interface formation. The transition-metal-free protocol does not demand column chromatography purification and results in highly pure indole fused α-hydroxy amides in good to excellent yields. Reusability of the catalytic system up to five cycles and extension to a gram-scale reaction are the key advantages of this transformation. The mechanisticstudy involving
通过使用固-液界面形成水中的催化量的K 3 PO 4和n Bu 4 NBr作为溶剂,首次开发了一种温和且操作简单的吲哚与α-酮酰胺的弗瑞德-克来夫斯羟烷基化方法。不含过渡金属的方案不需要柱色谱纯化,并且可以以高至优异的收率得到高纯度的吲哚稠合的α-羟基酰胺。这种转化的关键优势是催化系统最多可重复使用五个循环并扩展至克级反应。涉及1 H NMR实验的机理研究表明,反应是通过离子交换途径进行的。
Catalyst- and Additive-Free Chemoselective Transfer Hydrogenation of α-Keto Amides to α-Hydroxy Amides by Sodium Formate
A catalyst‐ and additive‐free chemoselective transfer hydrogenation of α‐keto amides to α‐hydroxy amides is easily achieved by using sodium formate as a hydrogen source. Control experiments suggest that the NH group of α‐keto amides is crucial for the chemoselective reduction through the formation of hydrogen bonds.