NHPI/O₂‐Mediated Electrochemical Intermolecular Cyclization/Dehydrogenation for the Construction of Polycyclic Quinazolinones

Abstract

Herein, an eco‐friendly and atom‐economical electrochemical methodology with isatins and 1,2,3,4‐tetrahydroisoquinolines through NHPI/O2‐mediated intermolecular oxidation/annulation is disclosed, leading to a variety of polycyclic quinazolinones in 46–82% yields. This oxidative cyclization proceeded in transition metal‐ and strong oxidant‐free conditions and generated H2 and CO2 as byproducts. Additionally, late‐stage functionalization and broad substrate scope demonstrated the synthetic usefulness of this protocol.

Visible-light promoted radical cascade cyclization of 3-allyl-2-arylquinazolinones for the synthesis of phosphorylated dihydroisoquinolino[1,2-b]quinazolinones

“…7 In consequence, the construction of such scaffolds has also been one of the attractive fields in organic synthesis. 15 Based on our continuing interest in the synthesis of heterocyclic compounds and phosphorus-containing molecules, 16 we herein report a visible-light promoted metal-free phosphorylation/arylation reaction of unactivated alkenes to construct phosphorylated dihydroisoquinolino[1,2- b ]quinazolinones with 3-allyl-2-arylquinazolinones as a new class of radical acceptors and with P(O)–H compounds as phosphoryl radical precursors (Scheme 1e).…”