Palladium(II)-Catalyzed Intramolecular [2 + 2 + 2] Annulation of Indolyl 1,3-Diynes: Construction of Azepino-Fused Carbazoles

Org Lett. 2023 Jun 30;25(25):4615-4620. doi: 10.1021/acs.orglett.3c01186. Epub 2023 Jun 21.

Abstract

A novel palladium(II)-catalyzed intramolecular [2 + 2 + 2] annulation of indolyl 1,3-diynes is described in this contribution. A variety of azepino-fused carbazoles are obtained in moderate to excellent yields. The key to the success of this transformation is the use of a carboxylic acid as an additive. This protocol features broad functional group tolerances, easy handling in air, and 100% atom economy. Furthermore, scale-up reactions, late-stage derivatizations, and photophysical property investigations highlight the potential synthetic utility of this methodology.

MeSH terms

  • Carbazoles*
  • Catalysis
  • Diynes*
  • Palladium

Substances

  • Carbazoles
  • Diynes
  • Palladium