Poly(N-isopropylacrylamide-co-L-proline)-catalyzed Claisen–Schmidt and Knoevenagelcondensations: unexpected enhanced catalyticactivity of the polymer catalyst†

Hao Zhang^‡,a,b, Mengting Han^‡,a,b, Tian Chen^a,Lin Xu^a,band Lei Yu^*,a,b

aInstitute of Pesticide, School of Chemistry and Chemical Engineering, School ofHorticulture and Plant Protection, Yangzhou University

bJiangsu Yangnong Chemical Group Co. Ltd.

†Electronic supplementary information (ESI) available: Condition optimizationtable, mechanism study details, product characterization, and 1H and 13C NMRspectra of the products. See DOI: 10.1039/c7ra09412d

‡Both authors contributed equally to this work.

Abstract:The polymer catalyst is more effective than the corresponding monomer catalyst? Yes! Theprolinemodified polymer, poly(N-isopropylacrylamide-co-L-proline), was unexpectedly found to be moreeffective than the corresponding monomer L-proline catalyst in Claisen–Schmidt and Knoevenagelcondensation reactions. 1H NMR, GC analysis and control reactions revealed that this abnormalphenomenon might be attributed to an enhanced concentration of the reactant on the surface of thepolymer catalyst, which might be due to adsorption of the reactants to the polymer through hydrogenbonding of the proline moiety with the reactants. This new polymer catalyst was so robust that it couldbe reused at least 10 times without deactivation. The polymer-catalyzed method was rather tolerant ofsubstrates bearing sensitive groups that are usually incompatible with conventional acid- or basecatalyzed methods, reducing the protection–deprotection steps of the substrates.

RSC Advances,2017,7, 48214–48221. IF=3.108

文章链接:http://pubs.rsc.org/en/content/articlelanding/2017/ra/c7ra09412d#!divAbstract