4-Chloro-2-formylbenzoic AcidÂis a useful reagent to prepare 3-(3-oxoalkyl)isocoumarins by tandem reductive rearrangement of 3-furylphthalides. ÂIt is also a suitable compound to synthesize 2-substituted-3-(1H-indol-3-yl)isoindolin-1-one derivatives in water without catalyst.