Divergent reactivity in palladium-catalyzed annulation with diarylamines and α,β-unsaturated acids: direct access to substituted 2-quinolinones and indoles.
A palladium-catalyzed CH activation strategy has been successfully employed for exclusive synthesis of a variety of 3-substituted indoles. A [3+3] annulation for synthesizing substituted 2-quinolinones was recently developed by reaction of α,β-unsaturated carboxylic acids with diarylamines under acidic conditions. In the present work, an analogous [3+2] annulation is achieved from the same set of starting materials under basic conditions to generate 1,3-disubstituted indoles exclusively. Mechanistic studies revealed an ortho-palladation-π-coordination-β-migratory insertion-β-hydride elimination reaction sequence to be operative under the reaction conditions.
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India).
Rajesh
R
Kancherla
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India).
Togati
T
Naveen
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India). dmaiti@chem.iitb.ac.in.
Debabrata
D
Maiti
D002384:Catalysis; D007211:Indoles / Q000138:chemical synthesis; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D015363:Quinolones / Q000737:chemistry*
D007211:Indoles; D015363:Quinolones; D010165:Palladium
CH activation; amines; carboxylic acids; indoles; palladium