ol9b04626_si_002.pdf (4.53 MB)

Lewis-Acid-Catalyzed Decarboxylative Annulation of 2‑Aminoindole-3-Carboxylate with Ynals Involving [3 + 2] Spirocycloaddition and 2,3-Aza Migration

Download (4.53 MB)
journal contribution
posted on 24.01.2020 by Manda Rajesh, Ravi Kumar, Surendra Puri, Jagadeesh Babu Nanubolu, Maddi Sridhar Reddy
2-Aminoindole-3-carboxylates undergo a Lewis-acid-catalyzed decarboxylative annulation with ynals to afford dihydrochromeno-fused δ-carbolines through a 2,3-aza migration, via a spirocyclic intermediate generated from an initial [3 + 2] spirocycloaddition. Brønsted acid interference changes the path from a [3 + 2] to a [4 + 2] addition. 2-Aminoindoles without an ester functional group at C3 underwent a different condensation, followed by hetero-Diels–Alder reaction to generate chromeno-fused α-carbolines.