A condition-tuned unorthodox approach to indole-3-carboxylic acids and anthranilic acids via carbon atom translocation.

We describe a robust one-pot cascade method for the synthesis of indole-3-carboxylic acids using isatins and DMSO via a one-carbon translocation involving in situ generation of α,ß-unsaturated methylvinylsulfoxide followed by amide bond cleavage and ring closure. The methodology has been extended to afford anthranilic acid derivatives by tuning the reaction conditions in the presence of molecular oxygen. Importantly, easy access to commercially available drugs, including tropisetron, is demonstrated.