Photochemical cascade cyclization of quinazolinone-tethered unactivated alkenes with α-halocarbonyls toward 2,3-fused quinazolinones

The divergent synthesis of 2,3-fused quinazolinones <i>via</i> photocatalytic tandem cyclization has been disclosed. It features green reaction conditions, good functional group compatibility and applicability to gram-scale synthesis. In particular, the precursors of tertiary carbon radicals with high steric hindrance are suitable for this reaction. Mechanistic experiments indicate that a radical cascade cross-coupling/cyclization process is involved. This is an efficient example demonstrating the direct activation of inactive α-halocarbonyls to furnish alkyl radicals for the synthesis of polycyclic quinazolinones.