Green Photoredox Catalysis: A Sustainable Approach for C–H Functionalization in Modern Organic Synthesis

Abstract

Green photoredox catalysis has become a revolutionary and green approach to contemporary organic synthesis, especially in the functionalization of unreacted CH bonds. Conventional synthetic procedures tend to be based on severe reaction conditions, toxic materials and energy-intensive reactions, creating environmental and economic issues. Conversely, photoredox catalysis is a renewable energy source that employs visible light to catalyze chemical reactions at mild conditions. This qualitative research paper examines the theory, mechanistic, and recent developments in green photoredox catalysis to C-H functionalize. The methodology is based on an extensive review and thematic analysis of recent literature (2021–2025), focusing on catalytic systems, reaction efficiency, sustainability, and applications in pharmaceuticals and material sciences. The results show that photoredox catalysis allows selective activation of C-H bonds through single-electron transfer processes, which allow the formation of reactive radical intermediates in environmentally friendly conditions. Moreover, metallaphotoredox systems and low-energy light-driven processes have greatly enhanced the efficiency and scalability of the reactions. The paper identifies green photoredox catalysis as a promising addition to sustainable chemistry, due to its ability to minimize waste, energy usage, and use of hazardous reagents. Nevertheless, the stability of catalysts, scalability, and mechanistic complexity are still topics of further research. On the whole, photoredox catalysis has become increasingly a key in green and sustainable organic synthesis, as highlighted in this study.

Keywords: Green chemistry; Photoredox catalysis; C–H functionalization; Visible light catalysis; Sustainable synthesis; Radical reactions; Metallaphotoredox; Organic synthesis.