Recyclable Palladium-Catalyzed Carbonylative Cyclization of Aryl Iodides and 2-Hydroxyacetophenones towards Flavones

A highly efficient heterogeneous palladium-catalyzed carbonylative cyclization of aryl iodides and 2-hydroxyacetophenones is developed. The reaction proceeds efficiently in DMSO at 120 degrees C under 3 bar of carbon monoxide by using 2 mol% of an MCM-41-immobilized bidentate phosphine palladium complex [MCM-41-2P-Pd(OAc)(2)] as the catalyst and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the base, providing a general, efficient and practical approach for the assembly of a wide variety of flavones in mostly good to high yields from readily available starting materials. This supported palladium catalyst can be easily recovered via centrifugation of the reaction mixture and recycled more than nine times without any significant loss of its catalytic efficiency.

Automated summary

A highly efficient method for carbonylative cyclization has been developed using a supported palladium catalyst. This method allows for the synthesis of diverse compounds from readily available starting materials with high yields under specific conditions. The catalyst can be easily recovered and reused multiple times without significant loss of its catalytic efficiency.