A new class of solid supported chiral imidazolidinone organocatalysts for the catalytic reduction of imines with trichlorosilane has been developed. Polystyrene proved to be a more effective support than silica in terms of both chemical and stereochemical efficiency. Even with a loading as low as 1 mol% the best performing supported catalyst showed a remarkable activity and stereocontrol ability, promoting the reduction with stereoselectivities reaching 98% ee and in most cases ranging between 90-95% ee The general scope of the methodology and the good recyclability of the immobilized catalyst were demonstrated. The polystyrene-anchored chiral catalyst was also used to prepare packed bed reactors for the continuous flow synthesis of chiral amines, that were obtained in excellent yields and enantioselectivities. By exploiting the chiral organocatalytic reactor, the in-flow stereoselective synthesis of a common, immediate precursor of rivastigmine, of the calciomimetic (R)-NPS 568 and of Acrylamide (S)-A, currently under study for the treatment of neuropathic pain, was successfully accomplished.
Solid supported chiral N-picolylimidazolidinones: recyclable catalysts for the enantioselective,metal- and H2-free reduction of imines in batch and in flow mode / R. Porta, M. Benaglia, R. Annunziata, A. Puglisi, G. Celentano. - In: ADVANCED SYNTHESIS & CATALYSIS. - ISSN 1615-4150. - 359:14(2017 Jul 17), pp. 2375-2382.
|Titolo:||Solid supported chiral N-picolylimidazolidinones: recyclable catalysts for the enantioselective,metal- and H2-free reduction of imines in batch and in flow mode|
|Parole Chiave:||asymmetric catalysis; catalytic reactors; chiral amines; imine reduction; supported catalysts|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Progetto:||Piano Sviluppo Unimi - Programma Transition Grant - Horizon 2020 - Linea 1B. Progetto "Italia per l'Europa"|
|Data di pubblicazione:||17-lug-2017|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/adsc.201700376|
|Appare nelle tipologie:||01 - Articolo su periodico|
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