892674-05-4Relevant articles and documents
Transition-Metal-Free Synthesis of Heterobiaryls through 1,2-Migration of Boronate Complex
Paul, Swagata,Das, Kanak Kanti,Manna, Samir,Panda, Santanu
supporting information, p. 1922 - 1927 (2020/02/04)
The synthesis of a diverse range of heterobiaryls has been achieved by a transition-metal-free sp2–sp2 cross-coupling strategy using lithiated heterocycle, aryl or heteroaryl boronic ester and an electrophilic halogen source. The construction of heterobiaryls was carried out through electrophilic activation of the aryl–heteroaryl boronate complex, which triggered 1,2-migration from boron to the carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene, and indole are well tolerated. Finally, we have successfully demonstrated the gram scale synthesis of the intermediates for an anticancer drug and OLED material using our methodology.
A highly efficient and recyclable Fe3O4 magnetic nanoparticle immobilized palladium catalyst for the direct C-2 arylation of indoles with arylboronic acids
Zhang, Lei,Li, Pinhua,Liu, Can,Yang, Jin,Wang, Min,Wang, Lei
, p. 1979 - 1988 (2014/06/24)
A highly efficient Fe3O4 magnetic nanoparticle (MNP) immobilized palladium catalyst was prepared and applied to the direct C-2 arylation of indoles with arylboronic acids. The reactions generated the corresponding cross-coupling products in good yields. In addition, the supported catalyst with low loading (2.0 mol%) showed high stability and could be recovered and reused 8 times without significant loss of activity. The Royal Society of Chemistry 2014.
Palladium nanoparticles encapsulated in a metal-organic framework as efficient heterogeneous catalysts for direct C2 arylation of indoles
Huang, Yuanbiao,Lin, Zujin,Cao, Rong
experimental part, p. 12706 - 12712 (2011/12/04)
Highly dispersed palladium nanoparticles (Pd NPs) encapsulated in the mesoporous cages of the metal-organic framework (MOF) MIL-101(Cr) have been prepared by using the wetness impregnation method. The Pd NPs were characterized by powder X-ray diffraction (PXRD), N2 adsorption, transmission electron microscopy, inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS). The particles size ((2.6 ± 0.5) nm) of the obtained Pd NPs was in good agreement with the cage diameters (2.9 and 3.4 nm) of the MOF. The resulting Pd/MIL-101(Cr) catalyst exhibited extremely high catalytic activities in the direct C2 arylation of substituted indoles by using only 0.1 mol-% of the Pd catalyst. Moreover, the catalyst is easily recoverable and can be reused several times without leaching into solution and loss of activity. The combination of the highly dispersible Pd NPs within the accessible mesoporous cages and the favorable adsorption of the aryl halides on MIL-101 are suspected to be the main reasons for the observed high activities of the Pd/MIL-101(Cr) catalyst in the direct C2 arylation of indoles. MOF-encapsulated catalyst: Highly dispersed palladium nanoparticles encapsulated in the mesoporous metal-organic framework (MOF) MIL-101(Cr) exhibited high catalytic activities for the direct C2 arylation of substituted indoles with a range of substituted iodobenzenes (see figure) by only using a very low amount of the Pd catalyst (0.1 mol-%). The catalyst is easily recovered and can be reused several times without leaching into solution and loss of activity.
