Formal [4+2] Cycloaddition of Vinyl Benzoxazinones with Oxazol‐5‐(4H)‐Ones for Diastereoselective Construction of 3,4‐Disubstituted Dihydro‐2(1H)‐Quinolinones

Abstract

Catalyzed by Pd 2 (dba) 3 . CHCl 3 and PPh 3 , the formal [4 + 2] cycloaddition between vinyl benzoxazinones and oxazol-5-(4H)-ones proceeded readily and delivered 3,4-disubstituted dihydro-2 (1H)-quinolinones in the reasonable chemical yields with excellent diastereoselectivities. The relative stereochemical configuration of the title products was unambiguously characterized with the use of Xray diffraction analysis.

Recent Advances in Metal‐Catalyzed Decarboxylative Reactions of Vinyl Benzoxazinanones

“…Finally, some supplementary reported [32][33][34][35][36][37][38][39][40] on the research progress of vinyl benzoxazinones whose nitrogen atoms are not substituted by Ts in metalcatalyzed decarboxylative reactions.…”

“…In the same year, Bi et al reported in the presence of Pd 2 (dba) 3 •CHCl 3 and PPh 3 , vinyl benzoxazinones containing NÀ H moiety and oxazol-5-(4H)-ones took place efficiently and facilely under the optimal reaction conditions, and furnished pharmaceutically and medicinally important scaffolds 3,4-disubstituted dihydro-2(1H)-quinolinones in the reasonable chemical yields with excellent diastereoselectivities (Scheme 35). [36] In 2019, Volla and co-workers reported a highly diastereoselective cascade transannulation of N-sulfonly-1,2,3-triazoles and vinyl benzoxazinanones for accessing fused tricyclic imidazolidinones in a one-pot operation (Scheme 36). [37] The usefulness of this method was further demonstrated by a gram-scale reaction with 1.0 g of vinyl benzoxazinanone.…”

“…reported in the presence of Pd 2 (dba) 3 ⋅CHCl 3 and PPh 3 , vinyl benzoxazinones containing N−H moiety and oxazol‐5‐(4 H )‐ones took place efficiently and facilely under the optimal reaction conditions, and furnished pharmaceutically and medicinally important scaffolds 3,4‐disubstituted dihydro‐2(1 H )‐quinolinones in the reasonable chemical yields with excellent diastereoselectivities (Scheme 35). [36] …”

Synthesis of 2‐Quinolones based on Visible Light‐Catalyzed Annulation of Diazo compounds

“…[14,15] Recently, 2-quinolones were efficiently prepared via transition-metal catalysis. [16][17][18][19][20] Despite the advancement in the synthetic methods for the 2quinolones, there are still challenges remaining in terms of environmental friendliness and the requirement for high reaction temperature. Therefore, there is a strong demand for new synthetic routes that are metal-free and can operate in mild conditions for constructing these compounds.…”

Palladium‐Catalyzed Asymmetric [4+3] Cycloadditions of Indene‐2‐carbaldehydes with 4‐Vinylbenzoxazinanones Toward Polycyclic 5H‐Benzo[b]azepines

“…For example, catalytic asymmetric decarboxylative cycloaddition reactions of vinyl benzoxazinanones have been used to synthesize enantiopure nitrogencontaining heterocyclic compounds. [10] Recently, we developed a method for diastereo-and enantioselective palladium-catalyzed decarboxylative [4 + 3] cycloaddition reactions of 4-vinylbenzoxazinanones with azomethine imines to afford 1,2,4benzotriazepines. [11] Inspired by these results, we have been seeking a direct approach toward functionalized 1-benzazepines from easily accessible substrates.…”