Artikel
Visible‐Light Induced Trifluoromethylation/Cyclization of Unactivated Alkene‐Bound Quinazolinones
Herein, we reported a selective, mild method for the visible light-photocatalyzed trifluoromethylation and cyclization of unactivated tethered alkenes to provide tri- and tetracyclic quinazolinones. Trifluoroacetic acid and anhydride are inexpensive and readily available reagents for the process which proceeds without the addition of a strong oxidant. Broad substrate scope and the formation of 5- and 6-membered rings are demonstrated in 44-82% yields. Control experiments provide the basis for a proposed mechanism involving photocatalyzed SET from fac-Ir(ppy)3 to TFAA, and trifluoromethyl radical-mediated regioselective cyclization. The practicality of the protocol was illustrated by a gram-scale synthesis in 76% yield.
