Intramolecular Pd(II)-catalyzed oxidative biaryl synthesis under air: reaction development and scope.
New reaction conditions for intramolecular palladium(II)-catalyzed oxidative carbon-carbon bond formation under air are described. The use of pivalic acid as the reaction solvent, instead of acetic acid, results in greater reproducibility, higher yields, and broader scope. This includes the use of electron-rich diarylamines as illustrated in the synthesis of three naturally occurring carbazole products: Murrayafoline A, Mukonine, and Clausenine. A variety of side products have also been isolated, casting light on competing reaction pathways and revealing new reactivity with palladium(II) catalysis.
Center for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6J7, Canada.
Benoît
B
Liégault
Doris
D
Lee
Malcolm P
MP
Huestis
David R
DR
Stuart
Keith
K
Fagnou
D000388:Air; D000470:Alkaloids / Q000138:chemical synthesis*; D002227:Carbazoles / Q000138:chemical synthesis*; D002384:Catalysis; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*
D000470:Alkaloids; D002227:Carbazoles; C096080:clausenine; C522709:mukonine; C443728:murrayafoline A; D010165:Palladium