Synthesis of 3,3-disubstituted allyl isoindolinones via Pd-catalyzed decarboxylative allylic alkylation

[Display omitted] •A mild and high-yielding decarboxylative coupling reaction of isoindolinones was developed.•The reaction is tolerant of a range of functional groups, including those bearing relatively acidic protons.•The coupling reaction is leveraged to access the bioactive indolizidine framework. Herein, we report a mild palladium-catalyzed decarboxylative allylic alkylation of allyl ester-substituted isoindolinone substrates to afford a variety of 3,3-disubstituted isoindolinone derivatives. The decarboxylative coupling reaction tolerates a range of functional groups, including ketones and alkenyl halides, and does not require protection of the isoindolinone nitrogen. Additionally, the reaction was found to proceed in near-quantitative yield for most substrates evaluated. Based on the isolation of competing cyclopropane and protonation products, a reaction mechanism is proposed.