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
activated carbonyl compounds such as α‐keto amide, isatin, 1,2‐diketone, α‐keto ester, trifluoromethyl ketone, and phenylglyoxal derivatives were examined and most of the compounds underwent the reaction smoothly to provide the corresponding products in moderate to excellent yields. Moreover, chemoselective reactions of α‐keto amides in the presence of simple ketones were achieved. Also, the model reaction
Abstract A selective protocol for the synthesis of either α -ketoamides or quinoxaline derivatives under the same reaction conditions has been achieved simply by varying substitution number of amino-groups. The method features metal-free, room temperature and broad substrate scopes as well as no extra oxidant. This process applies to various substituent groups and gives products in moderate to good
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。