Preparation of Chitosan-supported Urea Materials and their Application in Some Organocatalytic Procedures

Description

An efficient and mild procedure was developed for the preparation of three chitosan-supported ureas containing electron-withdrawing groups. These catalysts were characterized and employed as organocatalysts in different transformations, including the enantioselective cyanosilylation of α-ketoesters and aldehydes, the asymmetric addition of formaldehyde tert-butyl hydrazone to prochiral α-ketoesters and a Friedel-Crafts reaction. Several parameters that can affect the activity and selectivity of the reactions were analysed. The supported catalysts can be reused for more than 10 cycles with only a small loss in their properties. Finally, theoretical DFT calculations were carried out to interpret the results of the catalysed reactions.

Abstract

Junta de Andalucía FQM 142, FQM 263, P09-AGR-4597, 2012/FQM 10,787

Abstract

Ministerio de Economía y Competitividad CTQ2016-78703-P, CTQ2016-76908-C2-1,2-P

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