Progress in the Synthesis of Organoselenium Compounds: Conventional Routes Versus Green Approaches.

Organoselenium chemistry has progressed from the early synthesis of simple selenoorganic molecules in the 20th century to advanced methodologies aligned with the principles of green chemistry. Conventional synthetic approaches, frequently dependent on hazardous reagents and organic solvents, are increasingly being replaced by environmentally benign strategies, including solvent-free reactions, aqueous and bio-based solvent systems, microwave-assisted synthesis, and mechanochemical techniques. These sustainable methodologies offer significant advantages, such as enhanced reaction efficiency, higher or comparable yields, reduced waste generation, improved safety, and lower environmental impact. In parallel, evolving regulatory standards and industrial practices are encouraging the adoption of greener synthetic protocols to minimize hazardous waste and support safer pharmaceutical manufacturing. This review systematically categorizes organoselenium compounds, highlighting their synthetic methodologies, structural characteristics, and biological activities. Overall, recent advances emphasize the therapeutic potential of organoselenium compounds and demonstrate the essential role of sustainable synthetic chemistry in the development of future medicinal agents.