Synthetic Studies toward 1,2,3,3a,4,8b-Hexahydro­pyrrolo­[3,2‑b]­indole Core. Unusual Fragmentation with 1,2-Aryl Shift

Base-assisted transformations of 2-(3-oxoindolin-2-yl)­acetonitriles were investigated. Unexpectedly, attempted reactions of substrates possessing nonprotected nitrogen atoms were accompanied by unusual extrusions of 2-arylacetonitriles, followed by a 1,2-aryl shift to afford 3-hydroxyindolin-2-ones. On the other hand, the reactions for N-alkyl derivatives of oxoindolines took the expected route by only providing 1,2,3,3a,4,8b-hexahydropyrrolo­[3,2-b]­indoles.