Dehydrative Allylic Amination in Water via a Polymer‐Supported Ruthenium Catalyst

Modern organic synthesis relies heavily on toxic, nonrenewable organic solvents that often generate large volumes of waste, particularly in pharmaceutical processes, where solvents account for over 80% of chemical waste. Conventional cross‐coupling reactions frequently require activated electrophiles, produce unwanted byproducts, and involve complex purification procedures. Herein, we report a solid‐supported ruthenium catalyst that enables dehydrative allylic amination in water, directly converting allyl alcohols and amines into allylic amines. The 2‐mercaptopyridine–ruthenium complex immobilized on an amphiphilic polymer efficiently catalyzed the reaction under mild aqueous conditions, producing only water as a byproduct. This method avoids halide‐based leaving groups, additives, and organic solvents, while addressing three key sustainability challenges in a single reaction system: solvent toxicity, waste generation, and purification complexity. Moreover, the catalyst was readily removed via filtration, eliminating the need for chromatographic purification. Given the significance of allylamines in medicinal chemistry, this environmentally benign strategy offers a practical step toward scalable green synthesis.