Knitting rigid aromatic building blocks using external crosslinkers has been developed into an effective strategy for the synthesis of porous polymers in recent years. Here, we report the synthesis of porous chiral phosphoric acids by this strategy. Moreover, these porous chiral phosphoric acids were found to enable highly enantioselective dearomatization reactions. Remarkably, after being reused for 10 runs, no obvious loss in catalytic activity and selectivity was observed. The features of high reactivity, selectivity, stability, and recyclability of these hyper-crosslinked porous chiral phosphoric acids are significant for practical catalyst design.

Herein, we report a highly efficient synthesis of enantioenriched aza-[3.3.1]-bicyclic enamines and ketones, a class of structural cores in many natural products, via asymmetric dearomatization of indoles with azodicarboxylates. The reaction is initiated by electrophilic amination and followed by aza-Prins cyclization/phenonium-like rearrangement. A newly developed fluorine-containing chiral phosphoric acid displays excellent activity in promoting this cascade reaction. The absence or presence of water as the additive directs the reaction pathway toward either enamine or ketone products in high yields (up to 93%) with high enantiopurity (up to 98% ee). Comprehensive density functional theory (DFT) calculations reveal the energy profile of the reaction and the origins of enantioselectivity and water-induced chemoselectivity.