Dearomative ipso -Cyclization to Spiropseudoindoxyls: An Extendable Approach To Access Indolo[3,2- c ]quinolinones and Isocryptolepine.

A metal-free oxidative intramolecular dearomative spirocyclization of indole-3-formyl-2-carboxamides has been developed for the first time, affording spiropseudoindoxyls in good yields. This domino process proceeds through sequential oxidation, decarboxylation and ipso -arylation. The unique feature of this approach includes the compatibility of N -protected-indole-2-carboxamides. Further, a hitherto unknown rearrangement of spiropseudoindoxyls to indoloquinolones has been achieved. The synthetic utility of this strategy has also been showcased by the construction of a natural alkaloid, isocryptolepine.