The easily available and efficient catalyst containing a benzimidazolium ligand and PdCl2(PPh3)(2) demonstrated excellent catalytic activity to construct the flavones and aurones, respectively. This reaction can be operated under mild conditions, affording the desired products in moderate to good yields. This protocol was used to prepare the flavones and aurones by a slight modification of amines. (C) 2013 Elsevier Ltd. All rights reserved.
Regioselective Synthesis of Aurone Derivatives via PBu<sub>3</sub>-Catalyzed Cyclization of 2-Alkynoylphenols
Auronederivatives were synthesized in good to high yields by PBu3‐catalyzed intramolecular 5‐exo cyclization of 2‐alkynoylphenols. The reaction proceeds in high regioselectivity without forming 6‐endo cyclization products.