我们已经开发出了一种使用容易获得的硼氧烷(脱水硼酸)作为偶联伙伴,对吲哚进行Pd(0)催化的脱芳香基syn 1,2-二芳基化的方案。该反应使用P t Bu 3作为配体有效地进行,以发散地接近稠合的二氢吲哚,同时最小化直接铃木偶联的程度。反应的范围非常广泛,所有产物均以单一非对映异构体的形式获得,产率中等至优异。我们还编辑了一些数据,这些数据使底物和环硼氧烷的空间和电子特性与直接Suzuki偶联过程中经历所需的脱芳香性过程的倾向相平行。
抽象的 吲哚支架的合成主要依靠N保护的链烯基苯胺的C–H氧化胺化作用进行C–N分子内环化反应。在此,在没有催化N的情况下,通过在催化量的FeF 2存在下使用K 2 S 2 O 8作为氧化剂,将各种容易制备的2-烯基苯胺以高收率转化成所需的吲哚产物。K 2 S 2 O 8 / FeF 2系统为3-芳基吲哚提供了直接而良性的合成途径,适用于包括药物中间体在内的各种取代的吲哚。 吲哚支架的合成主要依靠N保护的链烯基苯胺的C–H氧化胺化作用进行C–N分子内环化反应。在此,在没有催化N的情况下,通过在催化量的FeF 2存在下使用K 2 S 2 O 8作为氧化剂,将各种容易制备的2-烯基苯胺以高收率转化成所需的吲哚产物。K 2 S 2 O 8 / FeF 2系统为3-芳基吲哚提供了直接而良性的合成途径,适用于包括药物中间体在内的各种取代的吲哚。
Aqueous Titanium Trichloride Promoted Reductive Cyclization of
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‐Nitrostyrenes to Indoles: Development and Application to the Synthesis of Rizatriptan and Aspidospermidine
TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp2)–H amination process. A range of functions such as halides (Cl, Br), carbonyl (ester, carbamate), cyano, hydroxy, and amino groups were tolerated. From β,β‐disubstituted o‐nitrostyrenes, 2,3‐disubstituted indoles were formed by a domino reduction/cyclization/migration process. Mild conditions, simple experimental procedure
The direct C3-arylation of N-unsubstituted indoles with arylchlorides and triflates has been realized using a palladium–dihydroxyterphenylphosphine (DHTP) catalyst. The site selectivity is different from that obtained with other structurally related ligands. This unique feature of the DHTP ligand is attributed to complex formation between the lithium salts of the ligand and the indole. The method
Direct C3-Selective Arylation of N-Unsubstituted Indoles with Aryl Chlorides, Triflates, and Nonaflates Using a Palladium–Dihydroxyterphenylphosphine Catalyst
successfully applied to the direct C3-arylation of N-unsubstituted indoles with arylchlorides, triflates, and nonaflates. This catalyst showed C3-selectivity, whereas catalysts with other structurally related ligands exhibited N1-selectivity. Complex formation between the lithium salts of the ligand and the indole is assumed to accelerate the arylation at the C3 position. Reactions using 3-alkylindoles afforded
Temperature Controlled Selective C–S or C–C Bond Formation: Photocatalytic Sulfonylation versus Arylation of Unactivated Heterocycles Utilizing Aryl Sulfonyl Chlorides
作者:Santosh K. Pagire、Asik Hossain、Oliver Reiser
DOI:10.1021/acs.orglett.7b03790
日期:2018.2.2
A visible-light-inducedphotocatalytic method for the arylsulfonylation of heterocycles has been developed. The synthetic utility of this reaction is reflected by the direct use of commercially available sulfonyl chlorides and heterocycles under room temperature conditions. Complementarily, the photocatalytic arylation of heterocycles by sulfonyl chlorides via extrusion of SO2 is feasible at elevated
On the Barton Copper‐Catalyzed C3‐Arylation of Indoles using Triarylbismuth bis(trifluoroacetate) Reagents
作者:Ahmed Fnaiche、Bianca Bueno、Claire L. McMullin、Alexandre Gagnon
DOI:10.1002/cplu.202200465
日期:——
The C3-arylation of C2-substituted indoles using Barton's protocol is investigated. The reaction is performed using triarylbismuth bis(trifluoroacetates) and is catalyzed by copper bis(trifluoroacetate). The reaction operates under mild conditions, shows excellent substrate scope, and demonstrates good function group tolerance. Electron neutral or poor aryl groups substituted at any position are efficiently