BF3 ⋅ OEt2 and Visible Light‐Controlled [3,3]‐ or [1,3]‐Rearrangement of Quinazolinone N−O Aryl Moieties

Abstract We described a base‐promoted O ‐arylation of N3‐hydroxyl quinazolinones with diaryliodonium salts and sequential BF 3 ⋅ OEt 2 and visible light‐controlled [3,3]‐ or [1,3]‐rearrangements of quinazolinone N−O aryl moieties to prepare a variety of 2‐(quinazolin‐4‐yloxy)phenols and atropisomeric 3‐(2‐hydroxyphenyl)quinazolin‐4‐ones in 44%‐75% yields and 28%‐70% yields, respectively. Mechanistic studies showed that HBF 4 generated in situ from BF 3 ⋅ Et 2 O and water served as the catalyst in this process and aryloxyquinazolinium salts are vital intermediates promoting the [3,3]‐ or [1,3]‐rearrangements. The N−O aryl moieties of aryloxyquinazolinium salts were found to undergo solely [3,3]‐rearrangement with heating whereas [1,3]‐rearrangement occurred via a radical process under irradiation of visible light. This method highlights the formation of aryloxyquinazolinium salts based on the use of BF 3 ⋅ OEt 2 and visible light to prompt [1,3]‐rearrangement generating atropisomeric quinazolinones.