Palladium-catalyzed dicarbonylation of terminal alkynes: A redox-neutral strategy for the synthesis of maleimides

A palladium-catalyzed redox-neutral dicarbonylation of terminal alkynes has been reported, in which hydroxylamine acts as both a nucleophile and a potential oxidant. Maleimides were synthesized in moderate yields under relatively mild conditions while avoiding the addition of equivalent oxidants. This reaction process involves two key steps: the addition of Pd-H to the terminal alkyne, and the hydroxylamine ester intermediate play the role of an internal oxidant via nucleophilic attack by hydroxylamine. This reaction has a wide range of functional group compatibility, and this internal oxidation reaction process also provided a new idea for other oxidative carbonylation reactions.