C–C cross-couplings via plant-derived biosurfactant micellar catalysis: A path toward reduced process toxicity

The use of sustainable, low-toxicity reaction media remains a major challenge in modern organic synthesis. In this paper, we report the use of Plantacare 2000 (PL-2000), a fully biodegradable biosurfactant derived from renewable plant sources, as a micellar reaction medium for palladium-catalysed cross-coupling reactions in water. Aqueous PL-2000 solutions proved effective for Suzuki-Miyaura, Cassar-Heck-Sonogashira, and Mizoroki-Heck reactions, capitalising on ”in-water” chemistry and ”on-water” reactivity. This resulted in good conversions (up to 99%) with various iodoarenes featuring electron-donating and electron-withdrawing substituents, heterocycles, and functionalised alkynes and alkenes. The biosurfactant demonstrated comparable, and in some cases superior, efficacy to conventional fossil fuel-derived surfactants such as TPGS-750-M and Brij-30, as well as to pure water or ethanol. Furthermore, the reaction could be performed with low catalyst loading and allowed for recycling in all reported examples. Green chemistry metrics, including atom economy, carbon efficiency, reaction mass efficiency, stoichiometric factor, and E-factor, were calculated and compared to literature procedures. These findings demonstrate that PL-2000-based synthetic protocols offer superior or comparable sustainability profiles, with reduced toxicity and improved biodegradability of the final waste. This confirms PL-2000’s versatility and environmental friendliness as a surfactant for transition-metal-catalysed organic transformations.