Solid Supported 9-Amino-9-deoxy-epi-quinine as Efficient Organocatalyst for Stereoselective Reactions in Batch and Under Continuous Flow Conditions

Polystyrene‐supported 9‐amino‐9‐deoxy‐epi‐quinine was synthesized through co‐polymerization of an ad hoc‐designed chiral monomer with divinylbenzene, in the presence of azobis(isobutyronitile) (AIBN) as radical initiator and toluene and 1‐dodecanol as porogenic solvents. The heterogenized catalyst efficiently promoted the reaction of isobutyric aldehyde with β‐nitrostyrene, in very high yield and enantioselectivity, comparable or even higher than that of the homogeneous counterpart (up to 95% ee). The recyclability of the catalyst, its general applicability and its successful application to other reactions was also demonstrated. Finally, for the first time, a 9‐amino‐epi‐quinine derivative was employed to perform an enantioselective Michael reaction under continuous‐flow conditions; by using a home‐made, packed‐bed catalytic reactor, the aldehyde addition to nitrostyrene was successfully realized in flow mode, leading to the product in up to 93% ee.