A Ligand/Additive/Base‐Free C(sp²)‐H Activation and Isocyanide Insertion in PEG‐400: Synthesis of Indolizine/Imidazoline‐Fused Heterocycles

Abstract

A ligand/base/metal oxidant free Pd‐catalyzed C(sp2)–H activation, followed by isocyanide insertion to synthesize indolizine/imidazoline fused heterocyclics in PEG‐400 as a recyclable solvent. The present transformation is greener and an efficient strategy using oxygen as external oxidant. The spectroscopic properties of selected indolizine/imidazoline fused heterocyclics were studied by UV−visible and fluorescence spectroscopy.

Recent Advances in Green Synthesis of Functionalized Quinolines of Medicinal Impact (2018‐Present)

“…The heterocyclic analogues well define the drug discovery development process due to their high potential screening for bioactivity and raise the demand for new drugs. Heterocyclic chemistry constitutes the synthesis, properties and biological applications with vast structural modification of the heterocyclic compounds in recent decades [17,18a–c] . The strategy to insert nitrogen containing heterocyclic moiety in structural reframing of natural products or any synthetic analogues of pharmaceutical compounds is traditionally beneficial due to dual nature of nitrogen atom, carrying a positive charge as well as acting as hydrogen bond donor or acceptor that greatly affect the strong interaction between target and the synthesized molecule [19a–f] …”

Palladium-Catalyzed [2 + 2 + 2] Annulation via Transformations of Multiple C–H Bonds: One-Pot Synthesis of Diverse Indolo[3,2-a]carbazoles

“…Catalysts such as Rh and Pd have been well-investigated for this purpose by Jiao et al, Dong et al, Miura, Satoh, and co-workers, Cheng et al, Li et al, and others. , However, to date, the multiple C–H transformation–annulations of alkynes remain limited . As part of our ongoing studies on the development of newer methodologies for functionalized heteroaromatics and fused indoles and in continuation of our interest, we investigated multiple Pd-catalyzed C–H transformation–annulations between indoles and alkynes for the first time. In the cascade reaction, three new C–C bonds are rapidly formed to build the molecular complexity, such as indolo­[3,2- a ]­carbazoles.…”