Convenient Synthesis of 3‐Glycosylated Isocoumarins

A new route for the synthesis of 3‐substituted and 8‐hydroxy‐3‐substituted isocoumarins was developed by modified Julia olefination for initial C–C bond formation between aldehydes and benzylic sulfones. Palladium‐catalyzed Meinwald rearrangement was used as a key step for the obtainment of ketone intermediates, which – upon base‐promoted intramolecular cyclization – afforded the desired isocoumarins. The developed method paves the way to hitherto unknown 3‐glycosylisocoumarins, in general, and 3‐glucosylisocoumarins, in particular, wherein the glucosyl moiety is attached to the pyrone ring of the isocoumarin framework.