Dearomative <i>ipso</i>-Cyclization to Spiropseudoindoxyls: An Extendable Approach To Access Indolo[3,2-<i>c</i>]quinolinones and Isocryptolepine
Chada Raji Reddy, Agnuru Theja, Ejjirotu Srinivasu, Muppidi Subbarao
Abstract
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.
Topics & Concepts
DominoChemistryIndole testIntramolecular forceDecarboxylationCombinatorial chemistryIndole alkaloidOxidative decarboxylationStereochemistryOrganic chemistryCatalysisAlkaloids: synthesis and pharmacologySynthesis and bioactivity of alkaloidsChemical synthesis and alkaloids