Noncovalently Functionalized Dendrimers as Recyclable Catalysts
作者:Debby de Groot、Bas F. M. de Waal、Joost N. H. Reek、Albertus P. H. J. Schenning、Paul C. J. Kamer、E. W. Meijer、Piet W. N. M. van Leeuwen
DOI:10.1021/ja005774u
日期:2001.9.1
The efficient reversible functionalization of the periphery of urea adamantyl poly(propylene imine) dendrimers with catalytic sites using noncovalent interactions is described. Phosphine ligands equipped with urea acetic groups, a binding motive complementary to that of the dendrimer host, have been prepared and assembled to the dendrimer support. The resulting supramolecular complex has been used as a multidentate ligand system in the palladium-catalyzed allylic amination reaction in a batch process and in a continuous-flow membrane reactor. We found that the activity and selectivity of the dendrimeric complex is similar to that of the monomer complex, which indicates that the catalytic centers act as independent sites. The size of the supramolecular system is sufficiently large and the binding of the guests is strong enabling a good separation of the catalyst components from the reaction mixture using nanofiltration techniques.
Palladium Complexes of Phosphane-Functionalised Carbosilane Dendrimers as Catalysts in a Continuous-Flow Membrane Reactor
作者:Debby de Groot、Joost N. H. Reek、Paul C. J. Kamer、Piet W. N. M. van Leeuwen
作者:Chan-Mo Yu、Ha-Soon Choi、Jongho Lee、Won-Hyuk Jung、Hyuk-Jun Kim
DOI:10.1039/p19960000115
日期:——
Treatment of N-but-2-enylpiperidine with acyl halides in the presence of K2CO3 afforded the corresponding Claisen products with high diastereoselectivity depending on the E or Z but-2-enyl geometry.