Palladium-catalyzed Sonogashira-coupling conjoined C-H activation: a regioselective tandem strategy to access indolo- and pyrrolo[1,2-a]quinolines.
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.
Synthetic Organic Chemistry Research Laboratory, Department of Chemistry, University of Delhi, Delhi, 110007, India.
Satya Prakash
SP
Shukla
Rakesh K
RK
Tiwari
Akhilesh K
AK
Verma
D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
D000480:Alkynes; D007093:Imidazoles; D007211:Indoles; D011758:Pyrroles; D011804:Quinolines; D010165:Palladium; C030374:indole