An oxidative cleavage of arene-condensed 4H-pyrans via the Grob–Wharton fragmentation

Abstract

When benzannulated dihydroindenochromene and dihydroxanthene derivatives were treated with m-chloroperoxybenzoic acid, oxidative cleavage of the pyran C=C bond and the formation of condensed ketolactones, the derivatives of oxonine-2,6-dione and oxecine-2,7-dione, took place. The reaction proceeded via epoxidation of the pyran double bond followed by the opening of the epoxide and Grob–Wharton fragmentation.