Domino reactions of 2H-azirines with acylketenes from furan-2,3-diones: Competition between the formation of ortho-fused and bridged heterocyclic systems

• DOI: 10.3762/bjoc.10.74
• Publication Date: 2014-04-04T08:39:12Z
• Authors: Alexander F Khleb...; Mikhail S Novikov; Viktoriia V Pakalnis; Roman O Iakovenko; Dmitry S Yufit
• Keywords: Pyrazine; Furan; Azirine; Domino

3-Aryl-2H-azirines react with acylketenes, generated by thermolysis of 5-arylfuran-2,3-diones, to give bridged 5,7-dioxa-1-azabicyclo[4.4.1]undeca-3,8-diene-2,10-diones and/or ortho-fused 6,6a,12,12a-tetrahydrobis[1,3]oxazino[3,2-a:3',2'-d]pyrazine-4,10-diones. The latter compounds, a new heterocyclic skeleton, are the result coupling two molecules azirine and acylketene can be prepared only from 3-aryl-2H-azirines having no electron-withdrawing groups in aryl substituent. Calculations at DFT B3LYP/6-31G(d) level for various routes bis[1,3]oxazino[3,2-a:3',2'-d]pyrazine skeleton formation revealed domino reaction occurring presence furandiones: acid-catalyzed dimerization dihydropyrazine followed consecutive cycloaddition acylketenes.