Efficient Synthesis of Highly Fused Quinazolinone Derivatives via Multiple C−C Bond Formations and 1,4‐Palladium Migration

An efficient palladium‐catalyzed annulation of 3‐arylquinazolinones with mono and double alkyne insertion was developed for the synthesis of fused quinazolinone derivatives in 43–80 % yields. A notable effect was observed in product yield, when bases/additives were modulated. The reaction mechanism is believed to proceed through C−X cleavage/alkyne insertion/1,4‐Pd migration and C−H annulation in a one‐pot manner. We have developed a mild and efficient palladium‐catalyzed annulation of 3‐(2‐halophenyl)quinazolin‐4(3H)‐ones with alkyne was developed for the synthesis of fused quinazolinone derivatives in 43–80 % yields. Notably, we observed remarkable changes in the product yield by modulating bases/additives.