Heterogenization of multicatalyzed cascade/ tandem reactions often suffers from the detrimental interactions of incompatible catalysts. Herein, double-shelled hollow mesoporous nanospheres with isolated sites of ProTMS/-CO 2 H in the outer shell and QNNH 2 /-SO 3 H or QDNH 2 /-SO 3 H in the inner shell were fabricated as highly stereoselective catalysts in heterogeneous Michael addition/αamination organocascade reactions. The spatial compartmentalization, evidenced by TEM-EDS elemental mapping, effectively suppressed the detrimental interaction of QNNH 2 , QDNH 2 , and −SO 3 H with ProTMS/-CO 2 H in the first-step Michael addition. The hollow interior, mesoporous shell, and thin shell thickness facilitated the mass transfer of intermediates into the inner shell where α-amination occurred.

Heterogeneous asymmetric multicomponent/multicatalytic organocascade faces the enormous challenges of tedious immobilization of catalysts, mass transfer, and stereoselective control. In this paper, the mesopore-abundant and well-shaped hollow mesoporous organic polymers, nanobowls (HMOPBs) and nanospheres (HMOPSs), are fabricated via emulsion polymerization of styrene on a polystyrene (PS) core and then removal of PS, accompanied by the adsorption of Co2+ ions, transformation of Co2+ into Co­(OH)2, and final removal of Co­(OH)2. Among them, the nanobowl HMOPBs­(a) with hollow interiors, mesoporous shells, and thin shell thickness (16 nm) possesses the largest surface area (185.7 m2 g–1) and displays the highest reaction kinetics in the sulfonation (2.85 mmol H+ g–1) and then immobilization of 9-amino­(9-deoxy)epi-quinine (QNNH2, 1.35 mmol g–1). For the 2,4-substituted bulky reactants in an asymmetric double-Michael cascade, the as-fabricated functional nanobowl can provide a suitable microenvironment to meet the requirements of the good to excellent double-Michael organocascades, which originates from its thin shell thickness and mesopore-dependent shell.

No abstract

The pioneered construction of monodisperse hollow and multihollow Jørgensen–Hayashi‐functionalized microspheres with a well‐defined spherical morphology, high surface area, and large pore volume were developed by initial dispersion copolymerization of the Jørgensen–Hayashi organocatalyst with acrylamide and styrene monomers cross‐linked by p‐divinylbenzene and ethylene glycol dimethacrylate, respectively, on the surface of poly(styrene/acrylic acid) (PS) microspheres to form core–shell structures, followed by removal of the PS core by etching in organic solvents. The as‐prepared hollow and multihollow microspheres were able to achieve better mass transfer in a complex heterogeneous asymmetric three‐component/triple cascade reaction and provided the products in good yields (31–61 %) with excellent stereoselectivities (80:20–93:7 dr, >99 % ee).

No abstract