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ABSTRACT: Lean on me: A soluble, "self-supported" chiral organosilica polymer (ChiOSP) with embedded imidazolidinone catalytic moieties was synthesized by a bottom-up strategy and applied as a highly efficient and recyclable organocatalyst for the asymmetric Diels-Alder reaction.
Chemistry - An Asian Journal 04/2013; · 4.50 Impact Factor
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ABSTRACT: The only way is up! "Bottom-up" construction of a robust chiral porous polymer (JH-CPP) embedded with the Jørgensen-Hayashi catalyst (JH) has been successfully achieved for highly efficient heterogeneous organocatalysis. The high BET surface area, wide openings and interconnected nanopores of JH-CPP increase the accessibility of catalytic sites and as such the catalyst shows excellent activity in catalyzing the asymmetric Michael addition reaction.
Chemistry 05/2012; 18(22):6718-23. · 5.93 Impact Factor
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ABSTRACT: We report herein for the first time the incorporation of a versatile organocatalyst, 4-(N,N-dimethylamino)pyridine (DMAP), into the network of a nanoporous conjugated polymer (NCP) by the "bottom-up" approach. The resulting DMAP-NCP material possesses highly concentrated and homogeneously distributed DMAP catalytic sites (2.02 mmol g(-1)). DMAP-NCP also exhibits enhanced stability and permanent porosity due to the strong covalent linkage and the rigidity of the "bottom-up" monomers. As a result, DMAP-NCP shows excellent catalytic activity in the acylation of alcohols with yields of 92-99 %. The DMAP-NCP catalyst could be easily recovered from the reaction mixture and reused in at least 14 consecutive cycles without measurable loss of activity. Moreover, the catalytic acylation reaction could be performed under neat and continuous-flow conditions for at least 536 h of continuous work with the same catalyst activity.
Chemistry 03/2012; 18(20):6328-34. · 5.93 Impact Factor
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ABSTRACT: We report a new method for the synthesis of hollow-structured phenylene-bridged periodic mesoporous organosilica (PMO) spheres with a uniform particle size of 100-200 nm using α-Fe(2)O(3) as a hard template. Based on this method, the hollow-structured phenylene PMO could be easily functionalized with MacMillan catalyst (H-PhPMO-Mac) by a co-condensation process and a "click chemistry" post-modification. The synthesized H-PhPMO-Mac catalyst has been found to exhibit high catalytic activity (98% yield, 81% enantiomeric excess (ee) for endo and 81% ee for exo) in asymmetric Diels-Alder reactions with water as solvent. The catalyst could be reused for at least seven runs without a significant loss of catalytic activity. Our results have also indicated that hollow-structured PMO spheres exhibit higher catalytic efficiency than solid (non-hollow) PMO spheres, and that catalysts prepared by the co-condensation process and "click chemistry" post-modification exhibit higher catalytic efficiency than those prepared by a grafting method.
Chemistry 05/2011; 17(22):6206-13. · 5.93 Impact Factor
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Advanced Synthesis & Catalysis 05/2011; 353(7):1174 - 1178. · 6.05 Impact Factor
