Ligand-free palladium-catalyzed intramolecular arylation of chromones: an expedient synthesis of 1-benzopyrano[3,2-c]quinolines

Synthesis of hitherto unreported 1-benzopyrano[3,2-c]quinolin-12-ones has been accomplished by a ligand-free Pd-catalyzed intramolecular C-H arylation protocol at the C-2 position of a chromone moiety in an Ugi product. (C) 2013 Elsevier Ltd. All rights reserved.