One-pot synthesis of spirofluorenyl- and spiroindeno[1,2- b ]indolyl oxindoles via sequential inter- and intramolecular Friedel–Crafts reactions

Modular Total Synthesis of the 5/5-Spirocyclic Spiroindimicins

Total syntheses of the 5/5-spirocyclic indoline alkaloids (±)-spiroindimicins B, C, D, E, F, and G have been achieved via a modular approach. Our route features direct coupling of halogenated pyrrolemetal and isatin partners, Suzuki coupling to append the indole unit, Lewis acid-mediated spirocyclization, and divergent functionalization to give various family members. These syntheses are concise (six or seven steps from commercial materials) and highly amenable to analogue synthesis.

A Tandem Nucleophilic Aminopalladation and Carbene Insertion Sequence for Indole Fused Polycycles

An efficient tandem nucleophilic aminopalladation and carbene insertion sequence is described for the synthesis of indole fused polycycles. The reaction process provides a variety of substituted indeno[1,2-b]indoles in up to 99% yields.

Solvent-specific, DAST-mediated intramolecular Friedel-Crafts reaction: access to dibenzoxepine-fused spirooxindoles

A facile, DAST-mediated intramolecular cyclization of 3-hydroxy-3-(2-((3-methoxybenzyl)oxy)phenyl)indolin-2-one derivatives for the synthesis of spirooxindoles fused with dibenzoxepine moieties is described. The success of this reaction is highly dependent on the choice of solvent (promoted by DCM and 1,2-DCE) and the electronic nature of the pendant aromatic ring, which is favored by the presence of electron-donating substituents. The reaction is believed to proceed through an intramolecular Friedel-Crafts-type reaction. Various dibenzoxepine-fused spirooxindoles were successfully synthesized in up to 98% yield. This methodology provides libraries of structurally diverse and medicinally important small molecules that could aid in the search for new bioactive molecules.