Compartmentalization of Multiple Catalysts into Outer and Inner Shells of Hollow Mesoporous Nanospheres for Heterogeneous Multi-Catalyzed/Multi-Component Asymmetric Organocascade

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/-CO2H in the outer shell and QNNH2/-SO3H or QDNH2/-SO3H in the inner shell were fabricated as highly stereoselective catalysts in heterogeneous Michael addition/α-amination organocascade reactions. The spatial compartmentalization, evidenced by TEM-EDS elemental mapping, effectively suppressed the detrimental interaction of QNNH2, QDNH2, and −SO3H with ProTMS/-CO2H 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.