For example, lenalidomide has been approved as a drug against multiple myeloma by the U.S. Food and Drug Administration (FDA) in 2004. Although various methods have been developed for the synthesis of isoindoles (e.g., reductive amination of phthalaldehydes, Diels-Alder reactions, retro-Diels-Alder reactions, intramolecular cyclization reactions ), drawbacks are apparent, including complicated synthetic procedures, harsh reaction conditions, and limited substrate scope, etc. Rh(III)- and Ru(II)-catalyzed C-H activation has been recently explored as an alternative strategy to address these issues. Despite the effectiveness, all these protocols employ acrylates for either migratory insertion-or aza-Michael addition-enabled ring closure, thus inevitably leaving one or two unintended, recalcitrant carboxylate ester groups in isoindoles; due to extra carbon atoms between isoindole skeleton and ester groups, it is extremely challenging, if not impossible, to completely remove these appendages.