Furo[2,3-<i>g</i>]thieno[2,3-<i>e</i>]indole: Application of an Ynamide-Based Benzannulation Strategy to the Synthesis of a Tetracyclic Heteroaromatic Compound

Abstract

The first synthesis of the tetracyclic aromatic compound furo[2,3- g]thieno[2,3- e]indole ("FTI") is described. The synthetic strategy features a photochemical benzannulation based on the reaction of an α-diazo ketone and ynamide which assembles a benzothiophene equipped with substituents that enable subsequent cyclizations to generate the nitrogen and oxygen heterocyclic rings.