Palladium-Catalyzed Sonogashira-Coupling Conjoined C–H Activation: A Regioselective Tandem Strategy to Access Indolo- and Pyrrolo[1,2-a]quinolines
摘要:
An operationally simple approach for the regioselective tandem synthesis of indolo[1,2-a]quinolines 4a-v and pyrrolo[1,2-a]quinolines 5a-k from 1-(2-bromophenyl)-1H-indole/pyrrole/imidazole 1a-c, 2a,b by the palladium-catalyzed sequential C-C bond formation is described. The developed approach involves the palladium-catalyzed Sonogashira coupling followed by the intramolecular C-C bond formation via C-H activation, which leads to the formation of 6-endo-dig cyclized product. This synthetic methodology accommodates wide functional group variation on alkyne, which proves to be advantageous for the structural and biological activity assessments.
Synthesis of pyrrolo[1,2-a]quinolines and ullazines by visible light mediated one- and twofold annulation of N-arylpyrroles with arylalkynes
作者:Amrita Das、Indrajit Ghosh、Burkhard König
DOI:10.1039/c6cc04366f
日期:——
Fused nitrogen heterocycles and ullazines are synthesised by one and twofold annulation of N-arylpyrroles with arylalkynes using metal free visible light photocatalysis.
Copper-Catalyzed Chemodivergent Cyclization of N-(<i>ortho</i>-alkynyl)aryl-Pyrrole and Indoles
作者:Tengfei Yao、Tong Xia、Wei Yan、Haofeng Xu、Fang Zhang、Yuanjing Xiao、Junliang Zhang、Lu Liu
DOI:10.1021/acs.orglett.0c01519
日期:2020.6.5
Herein, we described an efficient copper-catalyzed chemo-divergent tandem reaction of N-(ortho-alkynyl)aryl-pyrrole and (iso)indoles, delivering ring-fused N-heterocycles in good yields in an atom-economical manner. N-(ortho-alkynyl)aryl-pyrrole and indoles undergo the tandem cyclization/migration reaction, in which the group at 2-position was migrated to 3-position. In contrast, the dearomative cyclization of N-(ortho-alkynyl)aryl-isoindoles would occur to deliver the N-fused tetracyclic products efficiently.