Palladium-Catalyzed Domino Cycloisomerization/Double Condensation of Acetylenic Acids with Dinucleophiles

Metal-catalyzed cascade processes based on hydrofunctionalization of alkynes are receiving much more attention because their potential to provide advantageous approaches otherwise synthetically challenging compounds. An alternative catalyst system has been found for the domino cycloisomerization/cyclocondensation reaction involving acetylenic acids and heterodinucleophiles. A CNN pincer palladium(II) complex, acting as a homogeneous catalyst, provides corresponding polyheterocycles with higher substrate/catalyst ratio. Other palladium sources were also tested discarded, number mechanistic studies including poisoning assays, kinetic plots, TEM images, XRD spectra UPLC-MS analysis intermediates conducted in order shed light role this catalytic cycle involved reaction. As result, nuanced mechanism is tentatively proposed.