Copper-Catalyzed Aerobic Oxidative Ring Expansion of Isatins: A Facile Entry to Isoquinolino-Fused Quinazolinones

A copper-catalyzed aerobic oxidative ring expansion reaction of isatins with 1,2,3,4-tetrahydroisoquinoline for the synthesis of tetracyclic quinazolinones has been developed. This reaction is performed smoothly under simple conditions to give the corresponding products in moderate to good yields with good functional group tolerance. The capacity of the resultant 5H-isoquinolino[1,2-b]quinazolin-8(6H)-one for a range of palladium-catalyzed directing C-H activation has been further demonstrated, thus giving a broader access to diverse tetracyclic quinazolinones.

Automated summary

A copper-catalyzed aerobic oxidative ring expansion reaction has been developed for the synthesis of tetracyclic quinazolinones. The reaction proceeds smoothly under simple conditions, yielding moderate to good product yields with good functional group tolerance. The resulting 5H-isoquinolino[1,2-b]quinazolin-8(6H)-one has demonstrated a strong capacity for a range of palladium-catalyzed directing C-H activation, expanding the access to diverse tetracyclic quinazolinones.