A novel synthesis of 2-aryl-2H-indazoles via a palladium-catalyzed intramolecular amination reaction.
[reaction: see text] A variety of 2-aryl-2H-indazoles were synthesized by the palladium-catalyzed intramolecular amination of the corresponding N-aryl-N(o-bromobenzyl)hydrazines. Of several sets of reaction conditions surveyed, the combination of Pd(OAc)2/dppf/tBuONa gave the best results. This method applies to a wide scope of substrates containing electron-donating and electron-withdrawing substituents.
Song
J J
JJ
Department of Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, Connecticut 06877-0368, USA. jsong@rdg.boehringer-ingelheim.com
Yee
N K
NK
D000586:Amination; D002384:Catalysis; D007191:Indazoles / Q000138:chemical synthesis*; D010165:Palladium / Q000737:chemistry*
D007191:Indazoles; D010165:Palladium