Chapter 5.2 Five-membered ring systems: Pyrroles and benzo derivatives

Palladium-Catalyzed Sonogashira-Coupling Conjoined C–H Activation: A Regioselective Tandem Strategy to Access Indolo- and Pyrrolo[1,2-a]quinolines

“…Indole and pyrrole fused heterocycles are known to exert significant biological activity in many active pharmaceutical ingredients . Indolo- and pyrrolo­[1,2- a ]­quinolines are such molecules that have unique nitrogen containing tricyclic and tetracyclic structures derived from indole and pyrrole, and their reduced and oxidized forms occur widely among natural products . Along with antibacterial, antifungal and apoptosis inducing properties, these polycyclic compounds are also identified as rigid molecular platforms critical to advances in various areas of chemical research such as organic semiconductor chemistry, host–guest chemistry, liquid–crystal chemistry, and even biochemical studies of synthetic peptides …”

Exploring the Reactivity of N-Alkynylated Sulfoximines: Acid-Catalyzed Cyclizations

“…First, Perumal and co-workers utilized ynamides in a silver­(I)-catalyzed cyclization approach yielding indolo- or pyrrolo­[1,2- a ]­quinolines and naphtho­[2,1- b ]­thiophenes 5 (Scheme , middle), and second, in 2015, Yamaoka and Takasu developed Brønsted acid-promoted cyclization reactions of ynamides providing 3 H -pyrrolo­[2,3- c ]­quinolines 7 . As those fused heterocycles are found in natural products and possess a high potential as bioactive molecules, we started wondering if analogous reactions with N -alkynylated sulfoximines 6 would allow a direct access to sulfoximidoyl-tethered heterocyclic products 7 (Scheme , bottom). Herein, we report the realization of this concept applying a cyclization approach to the N -alkynylated substrates.…”

Synthesis of 5-Iodopyrrolo[1,2-a]quinolines and Indolo[1,2-a]quinolines via Iodine-Mediated Electrophilic and Regioselective 6-endo-dig Ring Closure

“…Among different N -heterocycles, indole and pyrrole rings are known to exert biological activity in many active pharmaceutical ingredients . Pyrrolo[1,2- a ]quinolines and indolo[1,2- a ]quinolines are such molecules which have unique nitrogen-containing tricyclic and tetracyclic stuctures derived from pyrrole and indole, and their reduced and oxidized forms occur widely among natural products . These polycyclic compounds are also identified as rigid molecular platforms critical to advances in various areas of chemical research such as host–guest chemistry, liquid crystal chemistry, and even biochemical studies of synthetic peptides …”