methodologies and occurs through a trifluoroacyl radical mechanism promoted by a photocatalyst, which triggers a C−O bond fragmentation. Mechanistic studies (kineticisotopeeffects, spectroelectrochemistry, optical spectroscopy, theoretical investigations) highlight the evidence of a fleeting CF3CO radical under photoredox conditions. The trifluoroacyl radical can be stabilized under CO atmosphere, delivering
我们报告了一种温和且操作简单的烯烃三氟酰化策略,该策略利用三氟乙酸酐作为低成本且易于获得的试剂。这种光介导的过程与传统方法有着根本的不同,它通过由光催化剂促进的三氟酰基自由基机制发生,从而触发 CO 键断裂。机理研究(动力学同位素效应、光谱电化学、光谱学、理论研究)突出了转瞬即逝的 CF 3的证据光氧化还原条件下的 CO 自由基。三氟酰基自由基可以在 CO 气氛下稳定,提供具有更高化学效率的三氟乙酰化产物。此外,该方法可以通过简单地改变反应参数变成三氟甲基化协议。除了简单的烯烃外,该方法还允许小分子药物和常见药效团的化学和区域选择性功能化。
Silica-supported silver nanoparticles as an efficient catalyst for aromatic C–H alkylation and fluoroalkylation
作者:Mikhail N. Khrizanforov、Svetlana V. Fedorenko、Asiya R. Mustafina、Kirill V. Kholin、Irek R. Nizameev、Sofia O. Strekalova、Valeriya V. Grinenko、Tatiana V. Gryaznova、Rustem R. Zairov、Raffaello Mazzaro、Vittorio Morandi、Alberto Vomiero、Yulia H. Budnikova
DOI:10.1039/c8dt01090k
日期:——
temperature under nanoheterogeneous electrochemical conditions. Negligible oxidative leaching of silver from Ag0/+@SiO2 is recorded during the catalytic coupling of arenes with acetic, difluoroacetic and trifluoroacetic acids, which enables the good recyclability of the catalytic function of the Ag0/+@SiO2 nanostructure. The catalyst can be easily separated from the reaction mixture and reused a minimum of
Visible-light promoted oxidative cyclization of cinnamic acid derivatives using xanthone as the photocatalyst
作者:Bin Zhao、Bo Xu
DOI:10.1039/d0ob02417a
日期:——
coumarin derivatives via a tandem double bond isomerization/oxidative cyclization of cinnamic acids. Inexpensive and stable xanthone was used as the photocatalyst, and readily available Selectfluor was used as the oxidant. This method tolerates a wide range of functional groups and offers excellent chemical yields in general. Besides, the photocatalytic oxidative cyclization of cinnamic acid esters gives
Efficient ligand-free palladium catalyzed Mizoroki–Heck reaction allowed the formation of trisubstituted α-trifluoromethylacrylates. The reaction showed good chemical tolerance and furnished moderate to excellent yields of reaction. Silver salt additive proved to be essential for the reaction. The reaction has been then applied to the formation of 3-trifluoromethyl coumarins and analogues of therapeutic
α-Trifluoromethylacrylates were synthesized using efficient ligand-free palladium catalyzed Mizoroki-Heckreaction. With the alkyl trifluoromethylacrylates used as substrates, different catalytic systems were explored including Pd/C as a catalyst. Good to excellent yields were obtained with good chemical tolerance