Tailoring sulfoxidation: Multifaceted role of manganese porphyrins

In the current era of industrialization, catalytic oxidation processes play a pivotal role in synthesizing both fine and bulk chemicals. Various strategies have been employed using different metal complexes as catalysts to enhance efficiency and selectivity. In this context, extensive studies have been conducted on the oxidation of sulfur to sulfoxides and sulfones, utilizing diverse catalytic systems that are not only highly selective but also environmentally benign, in contrast to traditional methods that rely on harsh reaction conditions. The oxidized sulfur products remain a topic of great interest due to their widespread applications in medicinal chemistry, drug metabolism, and pharmaceutical industries. Among the different catalytic systems explored, manganese porphyrins have demonstrated remarkable efficiency in the presence of suitable oxidants. Numerous studies have been conducted under both homogeneous and heterogeneous conditions, utilizing manganese porphyrins with various substitutions and reaction parameters. Most of these studies incorporated additives such as imidazoles, pyridine, and piperidine, among which imidazole proved particularly effective, often yielding complete conversion with exceptional selectivity. Furthermore, the catalytic reactivity is significantly influenced by factors such as solvent choice, temperature, pH, and reaction time. Herein, we present a multifaceted role of manganese porphyrins in tailoring the sulfoxidation reactions, by analysing the impact of different reaction conditions and ligand modifications. Furthermore, we aim to provide deeper insights into optimizing these catalytic systems while also unravelling their mechanistic aspects. Moreover, this review underscores the significance of structural tuning in manganese porphyrins to enhance catalytic efficiency.