Metal-catalyzed rearrangements of 3-allenyl 3-hydroxyindolin-2-ones in the presence of halogenated reagents.

The reactions of 3-allenyl 3-hydroxyoxindoles with a variety of halogenated reagents in the presence of catalytic amounts of precious metal salts were explored. Both, rearrangement and oxycyclization reactions to give 4-(1-halovinyl)-quinolinediones or spirocyclic halooxindoles, respectively, are competitive pathways. The kind of functionalization is substrate and reaction conditions dependent.