1,3-Dipolar cycloaddition reactions of phthalic anhydrides with an azomethine ylide

Abstract

A series of phthalic anhydrides underwent a 1,3-dipolar cycloaddition reaction with <italic>N</italic>-benzylazomethine ylide to produce unstable spiro(isobenzofuran-1,5′-oxazolidin)-3-ones, which underwent a subsequent reductive ring-opening reaction to afford 1(3<italic>H</italic>)-isobenzofuranones.