A rapid access to substituted oxazoles via PIFA-mediated oxidative cyclization of enamides
摘要:
A facile and rapid access to multi-substituted oxazoles has been achieved under mild reaction conditions in a short reaction time. Reaction of enamides 1 with [bis(trifluoroacetoxy)iodo]benzene (PIFA) in trifluoroethanol (TFE) at room temperature for 15 min afforded the desired oxazoles 2 in moderate to excellent yields (58-98%). A wide range of functional group tolerance has been observed for these transformations. (C) 2017 Elsevier Ltd. All rights reserved.
Geometry Driven Intramolecular Oxidative Cyclization of Enamides: An Umpolung Annulation of Primary Benzamides with Acrylates for the Synthesis of 3-Methyleneisoindolin-1-ones
作者:Joydev K. Laha、Mandeep Kaur Hunjan、Rohan A. Bhimpuria、Deepika Kathuria、Prasad V. Bharatam
DOI:10.1021/acs.joc.7b00966
日期:2017.7.21
A palladium-catalyzed tandem oxidativeannulation of primary benzamides with acrylates via intermolecular N-alkenylation followed by intramolecular C-alkenylation yielded a stereoselective synthesis of (E)-3-methyleneisoindolin-1-ones. The study unveils, for the first time, that only E-enamides could undergo intramolecular oxidative cyclization under the optimized conditions to give isoindolinones
Magnetically recyclable palladium nanoparticles (Fe
<sub>3</sub>
O
<sub>4</sub>
‐Pd) for oxidative coupling between amides and olefins at room temperature
for the synthesis of magnetically recyclable palladium nanoparticles (Fe3O4‐Pd) is described. The catalytic application of the Fe3O4‐Pd nanoparticles was explored for the first time in oxidative coupling between amides and olefins. p‐Toluenesulfonic acid plays a significant role in the oxidative amidation reaction. The reaction proceeds at roomtemperature, resulting in (Z)‐enamides under ambient air
描述了一种方便的合成可磁回收钯纳米颗粒(Fe 3 O 4 -Pd)的方法。Fe 3 O 4 -Pd纳米颗粒的催化应用首次在酰胺和烯烃之间的氧化偶联中得到了探索。对甲苯磺酸在氧化酰胺化反应中起着重要作用。反应在室温下进行,在没有助催化剂和配体的情况下,在环境空气中生成(Z)酰胺。Fe 3 O 4的超顺磁性‐Pd有助于轻松,定量地从反应混合物中回收催化剂,并且可以重复使用多达三个连续周期,但催化活性会略有下降。
Stereoselective Chlorination and Bromination of Enamides and Enamines via an Electrostatic Attraction Effect Using (1,1-Diacetoxyiodo)benzene and a Halide Source
作者:Linlin Xing、Chunbao Li
DOI:10.1021/acs.joc.5b01603
日期:2015.10.16
structure of the intermediates, the conformations of which are controlled by the electrostatic attractions between the positively charged nitrogen atoms and the oxygen atoms of the carbonyl group. This type of electrostatic effect has never been reported in olefin halogenations. For this reason, the three-membered bromoniumion is only a minor intermediate in the enamine bromination pathway. These methods