Lewis acid-catalyzed cascade radical addition/cyclization for the synthesis of 3-substituted isoindolin-1-one derivatives

Radical addition reactions to 2-formylbenzoate-derived hydrazones in the presence of a Lewis acid were developed. Under the reaction conditions, the resulting products were readily converted into 3-substituted isoindolin-1-one derivatives. Diastereoselective synthesis of 3-substituted isoindolin-1-one derivatives was also established employing L-proline as a chiral auxiliary. The cascade radical addition–cyclization reaction allows direct access to 3-substituted isoindolin-1-one derivatives under tin-free conditions.