Efficient synthesis of 5-nitro-benzo[b]furans via 2-bromo-4-nitro-phenyl acetates
摘要:
Acetylation/Sonogashira cross-coupling reaction/cyclization has been carried out in one-pot using a Na2PdCl4/2-(di-tert-butylphosphino)-N-phenylindole/Cul system in TMEDA to give 5-nitro-2-substituted benzo[b]furans in excellent yields. We also describe the extension of this method to 4-EWG-2-bromophenols obtaining 2,5-disubstituted-benzo[b]furans in good yields. (C) 2010 Elsevier Ltd. All rights reserved.
Triple CH functionalization: Palladium‐catalyzed synthesis of benzofurans and coumarins by reacting phenols and unactivated olefins is described. The reaction comprises sequential CH functionalization and shows diverse functional group compatibility. Preliminary mechanistic studies shed light into the possible mechanisms.