Microwave-Assisted Catalytic Transfer Hydrogenation of Chalcones: A Green, Fast, and Efficient One-Step Reduction Using Ammonium Formate and Pd/C

Catalytic transfer hydrogenation (CTH) and microwave-assisted organic synthesis (MAOS) have each advanced the sustainability of reduction chemistry; however, their combined application to conjugated enones remains largely unexplored. To the best of our knowledge, no unified protocol has been reported for the rapid, one-pot conversion of chalcones into saturated alcohols under microwave irradiation. Herein, we report a concise and green method that integrates MAOS with Pd/C-catalyzed CTH, employing inexpensive ammonium formate in ethanol. In contrast to state-of-the-art hydrogenations that require pressurized H2 or costly metal complexes, our strategy (i) achieves complete conversion within 20 min at 60 °C, (ii) tolerates both electron-rich and electron-poor substrates, (iii) reduces nitro-substituted chalcones in a single step, and (iv) consumes < 0.005 kWh per reaction—an approximately 250-fold energy saving relative to conventional procedures. These results position microwave-driven CTH as a scalable alternative for synthesizing pharmacologically relevant saturated alcohol scaffolds from readily available chalcones.