Palladium-Catalyzed Sonogashira-Coupling Conjoined C–H Activation: A Regioselective Tandem Strategy to Access Indolo- and Pyrrolo[1,2-a]quinolines
2012
Shukla, Satya Prakash | Tiwari, Rakesh K. | Verma, Akhilesh K.
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.
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