Multifunctional hollow mesoporous organic polymeric nanospheres (HMOPs) as effective heterogeneous catalysts with enhanced activity in green asymmetric organocatalysis

The first controllable fabrication of hollow mesoporous organic polymeric nanospheres (HMOPs) with pure intriguing mesopores using low-cost and commonly available materials is developed by metal ion-adsorbed, in-situ forming metal hydroxide or phosphate-expanded technique and removal of templates. After sulfonated and immobilized by organocatalyst, the functional HMOPs displays significantly enhanced catalytic performances in heterogeneous asymmetric organocatalysis. [Display omitted] •First fabrication of hollow mesoporous organic polymers.•High acid capacity and effective immobilization of organocatalyst.•Enhanced catalytic performances due to hollow interior and mesoporous shell.•Asymmetric aldol addition and double-Michael organocascade in green manner.•Good reusability without significant loss in catalytic performances. Based on the unique advantages including hollow interior, mesoporous shell, well-defined morphology and good compatibility with organic reactants, the first controllable fabrication of hollow mesoporous organic polymeric nanospheres (HMOPs) with pure intriguing mesopores was developed using low-cost and commonly available materials via metal ion adsorption in outer shell, in-situ forming metal hydroxide or phosphate expansion and removal of templates. After being sulfonated by ClSO3H, the resulting Co(OH)2-templated HMOPs with the highest acid exchange capacity (2.67 mmol g−1) could effectively immobilize versatile 9-amino(9- deoxy)epi-cinchonidine organocatalyst (0.98 mmol g−1) via acid-base interaction without multi-step chemical modification. In the green asymmetric aldol addition and double-Michael organocascade reaction, the mesopore- abundant HMOPs exhibited significantly higher catalytic performances in yields, diastereoselectivities and enantioselectivities than mesopore-deficient HNs due to the ordered mesoporous (2–15 nm), amphipathic shell and hollow interior. Based on the unchanged spherical morphology and hollow mesoporous structure, HMOPs was proved to possess a good mechanical stability in recycled processes.