Development of macroporous polymer monolith immobilizing l-proline-based organocatalyst and application to flow asymmetric aldol addition reaction

Flow process has attracted attention in the field of fine chemical synthesis. The well-designed immobilized catalyst is powerful tool to realize practical and efficient flow process. A macroporous monolith is a self-standing material with three-dimensional through-pores which ensures large surface area and high permeability. In this study, polyacrylamide-based macroporous monolith containing_L-proline was developed and the porous properties of the monolith was evaluated. The internal structure of monolith was controlled by alcohol (ethanol, 1-butanol, 1-octanol, 1-dodecanol) used as porogen. In addition, the monolith was applied to asymmetric aldol addition reaction in flow system and achieved enantioselectivity of 61‒74% ee at residence time of 12 h. This is the first example that achieved flow asymmetric synthesis using porous polymer monolith with_L-proline.