[2 + 2 + 1] Heteroannulation of Alkenes with Enynyl Benziodoxolones and Silver Nitrite Involving C≡C bond Oxidative Cleavage: Entry to 3-Aryl-Δ<sup>2</sup>-isoxazolines
作者:Cheng-Yong Wang、Fan Teng、Yang Li、Jin-Heng Li
DOI:10.1021/acs.orglett.0c01285
日期:2020.6.5
A copper-catalyzed [2 + 2 + 1] heteroannulation of alkenes with enynyl benziodoxolones and AgNO2 involving oxidative cleavage of the C≡C bond promoted by cooperative Zn(OTf)2, KOAc, and 4 Å MS for producing 3-aryl Δ2-isoxazolines is reported. Mechanistic studies indicate that AgNO2 serves as the N/O two-atom unit source, enabling the formation of three bonds through NO2 addition across the C≡C bond
An efficient and generally applicable protocol for decarboxylative coupling of α,α‐difluoroarylacetic acids with ethynylbenziodoxolone (EBX) reagents has been developed, affording α,α‐difluoromethylated alkynes bearing various functional groups in moderate to excellent yields. Remarkably, this potassium persulfate (K2S2O8)‐promoted reaction employs water as solvent under transition metal‐free conditions
已经开发出一种有效且普遍适用的方案,用于将α,α-二氟代芳酸与乙炔基苯并恶唑酮(EBX)试剂进行脱羧偶联,从而以中等至极好的收率提供带有各种官能团的α,α-二氟甲基化炔烃。值得注意的是,这种过硫酸钾(K 2 S 2 O 8)促进的反应在无过渡金属的条件下将水用作溶剂,从而为α,α-二氟甲基化炔烃提供了绿色的合成方法。
1,2-Difunctionalization of Aryl Triflates: A Direct and Modular Access to Diversely Functionalized Anilines
作者:Seoyoung Cho、Qiu Wang
DOI:10.1021/acs.orglett.0c00320
日期:2020.2.21
ortho-Amino difunctionalization of aryl triflates has been achieved via a three-component reaction. The cascade reaction proceeds through a zincate base-mediated deprotonative formation of a reactive aryne intermediate, in situ nucleophilic addition, and coupling with electrophilic partners. This strategy leverages the advantageous reactivity of organozincate intermediates, enabling the installation
Silver-Catalyzed Trifluoromethylalkynylation of Unactivated Alkenes with Hypervalent Iodine Reagents
作者:Xinkan Yang、Gavin Chit Tsui
DOI:10.1021/acs.orglett.9b03230
日期:2019.11.1
unactivated alkenes is presented. The reaction is catalyzed by silver(I) trifluoroacetate for the simultaneous construction of two C-C bonds (alkyl-alkyne and alkyl-CF3). By employing versatile hypervalentiodinereagents, ethynylbenziodoxolones, useful trifluoromethylalkynylated compounds can be prepared from simple alkenes displaying excellent functional group tolerability. A radical mechanism is proposed
Visible‐light‐induced heterogeneous photocatalysis for decarboxylative alkynylation has been performed. The using of cheap, metal‐free and recyclable graphitic carbonnitride (g‐C3N4) as the photoredox catalyst in the process enables the facile transformation of a variety of carboxylic acids into structurally diverse alkyne‐containing molecular architectures under mild and environmentally‐benign conditions
可见光诱导的非均相光催化脱羧炔基反应。使用便宜,无金属且可回收的石墨氮化碳(g ‐ C 3 N 4)作为该过程中的光氧化还原催化剂,可以在温和和环境友好的条件下将多种羧酸轻松转化为结构多样的含炔分子结构。明显地,反应系统的非均质性质允许催化剂在多次运行中的回收和再利用而不损失反应性。光催化反应也可以以连续流动的方式进行并按比例放大至克级。此外,该策略在未活化烯烃的1,2氨基炔基化中的应用进一步凸显了该策略的制备能力。