Expanding the Toolbox of Heterogeneous Asymmetric Organocatalysts: Bifunctional Cyclopropenimine Superbases for Enantioselective Catalysis in Batch and Continuous Flow

Abstract A strategy for the immobilization of chiral 2,3‐bisaminocyclopropenium salt (pre‐catalyst) onto polystyrene and silica supports is presented together with a suitable procedure conversion into corresponding cyclopropenimine superbase catalysts. The activity recyclability polystyrene‐ silica‐supported cyclopropenimines were initially tested under batch conditions in model Michael addition detecting comparable efficiencies but superior stability latter heterogeneous catalyst (5 cycles, accumulated TON 27.1). preferred behaved very similarly to soluble counterpart reaction glycine imine different acceptors (48–92% yield; 60–98% ee ) it could be utilized as packing material fabrication fixed‐bed mesoreactors (pressure‐resistant stainless‐steel columns). Continuous‐flow experiments performed satisfactory long‐term (24 h on stream) unaltered efficiency enantioselectivity. magnified image