Synthesis of Pyrido[2,1-b]quinazolin-11-ones and Dipyrido[1,2-a:2′,3′-d]pyrimidin-5-ones by Pd/DIBPP-Catalyzed Dearomatizing Carbonylation

N-Fused heterocycles can be easily synthesized by palladium-catalyzed dearomatizing carbonylation using 1,3-bis(diisobutylphosphino)propane (DIBPP) as the ligand. Pyrido[2,1-b]quinazolin-11-ones were obtained from N-(2-bromophenyl)pyridine-2-amines in up to quantitative yield and dipyrido[1,2-a:2',3'-d]pyrimidin-5-ones from 3-bromo-N-(pyridine-2-yl)pyridine-2-amines in up to 84% yield. The cyclocarbonylation can be also realized without isolation of compound 1 and additional palladium catalyst.