Diastereoselective synthesis of succinimide-fused polycycles via intermolecular interception of indanone–allene intermediates with maleimides

A highly diastereoselective Pd-catalyzed sequential reaction of ortho-iodophenyl-ynones, propargylic ethers and maleimides is developed for efficient synthesis of tetracyclic succinimide derivatives containing three contiguous stereocenters and one exocyclic double bond. The reaction proceeds through Pd-catalyzed cross-coupling and propargyl Alder-ene reactions to generate a reactive indenone-allene intermediate, which undergoes an intermolecular Diels-Alder cycloaddition with maleimide to deliver a densely functionalized product. In addition, a formal four-component reaction was observed for generating polycyclic products bearing two succinimide motifs.