Visible-light-mediated synthesis of quinolines

Quinolines are N-heterocyclic privileged scaffolds that find immense applications in biological domains and materials science. For example, they act as antimalarial, anti-inflammatory, antiparasitic, antiviral, and anticancer agents. The nucleus of quinolines is abundant in natural products. Various classical approaches to synthesize quinolines are present in the literature. The majority of them involve low yield product formation, tedious workup, and large waste production, which ultimately adds to the environmental burden. Thus, the development of simple, mild strategies to forge such a potent nucleus is highly desirable. On the other hand, in the last five years, visible-light-mediated transformations have also caught significant attention as a greener and eco-friendly route by utilizing photons as a clean energy source. In this context, many researchers have experimented with the synthesis of quinolines under visible light irradiation. Thereby, this review is dedicated solely to the synthesis of quinolines enabled by visible light, wherein most of the described methodologies are accessible under the environment of a blue LED. This review covers the literature from the year 2015 to date.