Facile Access to Functionalized Spiro[indoline-3,2′-pyrrole]-2,5′-diones via Post-Ugi Domino Buchwald–Hartwig/Michael Reaction

A novel access to spiro[indoline-3,2'-pyrrole]-2,5'-diones is presented via a palladium-catalyzed post-Ugi cascade cyclization approach involving a Buchwald-Hartwig/Michael reaction sequence. The method allows the easy construction of a library of spirooxindoles in moderate to good yields starting from readily available precursors. In addition, alkynoic acids are replaced with α,β-unsaturated acids leading to variably substituted spirooxindoles.