Sulfone synthesis in the coupling era: a decade update

Sulfones represent a vital class of organosulfur compounds with broad significance across pharmaceuticals, agrochemicals, materials science, and synthetic chemistry. Traditional oxidation-based methods for sulfone preparation, while historically important, face limitations in chemoselectivity, functional-group tolerance, and environmental sustainability. Over the past decade, coupling-based approaches have emerged as powerful alternatives, enabling direct and modular sulfone-frameworks construction from readily available substrates. This review provides a comprehensive analysis of advances in transition-metal-catalyzed systems alongside transition-metal-free methodologies, including oxidative and photocatalytic sulfonylation strategies developed between 2015 and 2025. Particular emphasis is placed on copper, nickel, palladium, Silver, and Ruthenium catalysis, together with the growing implementation of magnetically recoverable nanocatalysts that offer enhanced efficiency and recyclability. The review also highlights visible-light-driven sulfonylation, oxidative radical methods, and the transformative role of practical SO2 surrogates such as DABSO(1,4-Diazabicyclo[2.2.2]octane bis(sulfur dioxide)) and sulfite salts. Mechanistic insights – ranging from radical cascades to organometallic cross-coupling and C – H functionalization – are discussed to illustrate the expanding reactivity landscape. Collectively, these innovations have significantly broadened the applicability of sulfone synthesis, enabling late-stage functionalization and improved sustainability. The review concludes with current challenges and future opportunities, underscoring the continued evolution of coupling-based sulfonylation as a critical platform for modern organic synthesis.