Synthesis of Bi‐functional Immobilized Polymer Catalysts via a Two‐step Radiation‐induced Graft Polymerization Process

Abstract

AbstractHere, we designed and synthesized two types of bi‐functional immobilized polymer catalysts based on the prolineamide‐acid combination for direct enantioselective aldol reaction in flow systems. Conventional bi‐functional catalysts in which the two functions are present on the same graft polymer afforded up to 99 % yield and >99 % enantiomeric excess (ee) in a recirculating flow system. We also investigated bi‐functional catalysts in which the two functions are located on different graft polymers. We present a straightforward catalyst immobilization method that allows two different catalysts located on different graft polymers to be introduced separately onto the same polymer by conducting two successive steps of radiation‐induced graft polymerization process (RIGP). We confirmed that the graft polymers (grafted polycatalyst and polyacrylic acid chain) interact with each other to promote the aldol reaction with high conversion and ee. This design strategy may be superior to the conventional approach for synthesizing catalysts in which multiple functions interact.