Continuous‐Flow Asymmetric Hydrogenation for the Synthesis of an (<i>S</i>)‐Metolachlor Intermediate Using Catalysts Immobilized on a Core/Shell‐Type Support

Here we show successful continuous‐flow synthesis of a key inter‐mediate of (<i>S</i>)‐Metolachlor, which is a widely used agrochemical that is in huge demand, with asymmetric hydrogenation using a heterogeneous catalyst immobilized on a core/shell‐type support. We have immobilized a state‐of‐the‐art homogeneous catalyst onto a core/shell‐type heterogeneous support that was developed in our laboratory, which successfully showed high turnover frequency and turnover number over a long period when used in a solvent‐free continuous‐flow manner. This result demonstrates the feasibility of continuous‐flow production of sophisticated chiral agrochemicals with packed‐bed heterogeneous catalysts. Moreover, the heterogenization protocol was shown to be applicable to elaborate practical catalysts used in industry, especially the group of phosphine ligands.