Preparative and regiochemical aspects of the palladium-catalyzed carbonylative coupling of 2-hydroxyaryl iodides with ethynylarenes

The title reaction has been conveniently carried out in DMF at 60°C unakr 1 atm of CO pressure using DBU as the base and Pd(OAc)z(DPPF)2 as the catalyst to t@ord generally muhtres offlavones 4 and atuones 5 in varying yields, dependtng on the mbstituents in the both reactants. Factors controlling the regioselectivtty for 4 or 5 formation in thts and in sunilar, previotuly reported . coupling procedwes have been examined.