A new approach to isoindolinone derivatives by sequential palladium iodide-catalyzed oxidative aminocarbonylation–heterocyclization of 2-ethynylbenzamides

A novel approach to functionalized isoindolinone derivatives 3 is presented. It is based on a cascade process, consisting of PdI2/KI-catalyzed oxidative monoaminocarbonylation of secondary 2-ethynylbenzamides 1 with nucleophilic secondary amines 2, followed by intramolecular conjugate addition of the arylamido group to the alkynylamido group of the intermediate alkynylamides. Products have been obtained in high to excellent yields starting from different N-alkyl 2-ethynylbenzamides and amines, under relatively mild conditions (100 °C under 40 atm of a 4:1 mixture of CO–air), working in a MeCN–amine mixture (2:1, v/v) for 5–15 h.