Access to Phosphine-Containing Quinazolinones Enabled by Photo-Induced Radical Phosphorylation/Cyclization of Unactivated Alkenes

Abstract

A mild and facile photo-induced cascade radical addition/cyclization of unactivated alkenes has been reported, through which a variety of biologically valuable phosphine-containing quinazolinones could be obtained in moderate to good yields. The protocol was characterized by mild conditions, broad substrate scope, and high atomic economy.

Radical Cascade Cyclization of Alkene‐Tethered Compounds: Versatile Approach towards Ring‐Fused Polycyclic Structures

“…In 2021, Jin and co‐workers utilized sulfonyl chlorides as sulfonyl radical sources to give sulfonylated ring‐fused quinazolinones (Scheme 49a) [86] . In 2022, Wu and co‐workers reported a photo‐induced cascade phosphorylation/cyclization of unactivated alkenes towards phosphine‐containing quinazolinones (Scheme 49b) [87] …”

Transition-metal-free radical difluorobenzylation/cyclization of unactivated alkenes: access to ArCF2-substituted ring-fused quinazolinones

“…Representative studies include the alkylation/cyclization, 7 acylation, 8 sulfonylation, 9 phosphorylation/cyclization of unactivated alkenes. 10 Despite the development of these methods, it is still highly desirable to develop practical and mild synthetic methods for construction of biologically important ring-fused quinazolinones bearing other bioactive functional groups or pharmacophores.…”

Radical-mediated photoredox hydroarylation with thiosulfonate

“…Subsequently, the radical A experiences an intramolecular radical addition to provide intermediate B , which is then oxidized through a single-electron transfer (SET) with *Ir III followed by deprotonation to produce the intermediate product 5a . 17 Finally the Ir II species was excited to highly reductive *Ir II , 18 which reduces 5a to the desired product 1a . Simultaneously, the aryl thiyl radical is regenerated during this step.…”