Intramolecular cyclisation catalysed by silver(I) ion; a convenient synthesis of aurones

Abstract

Silver(I) ion catalysed intramolecular cyclisation of R′C₆H₄CCCOC₆H₃(OH)R (1a–d) at room temperature gives the corresponding aurone (2a–d) as the major product with a trace amount of the flavone; compounds (1a–d) could be prepared by the addition of the corresponding lithium acetylide (4a–b) to the substituted salicyl aldehyde (5a–c), followed by MnO₂ oxidation.