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Multicomponent Approach to Silica‐Grafted Peptide Catalysts: A 3 D Continuous‐Flow Organocatalytic System with On‐line Monitoring of Conversion and Stereoselectivity
Author(s) -
Scatena Gabriel S.,
de la Torre Alexander F.,
Cass Quezia B.,
Rivera Daniel G.,
Paixão Márcio W.
Publication year - 2014
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201402501
Subject(s) - microreactor , chemistry , catalysis , derivatization , stereoselectivity , flow chemistry , triethoxysilane , combinatorial chemistry , chromatography , heterogeneous catalysis , organic chemistry , high performance liquid chromatography
The derivatization of organocatalysts with functional appendages suitable to anchor onto solid supports is usually achieved by stepwise syntheses. As an alternative to such a strategy, this work describes a one‐pot approach to silylated prolyl‐peptide catalysts by a multicomponent reaction that enables the simultaneous incorporation of the catalytic and the heterogenizable (triethoxysilane) moieties. A microreactor with high catalytic efficacy and reproducibly in the conjugate addition of aldehydes to nitroolefins was obtained by grafting onto HPLC‐grade silica (10 μm) and packing into a column with a selected catalyst. A 3 D continuous‐flow system that includes the on‐line monitoring of the reaction outcome was set up. For that, the microreactor was coupled to a chromatographic column for the separation of the remaining substrates from the Michael adduct in the second dimension, followed by a chiral polysaccharide column for the analysis of conversion and stereoselectivity. This approach represents a new instrumental setup that combines the advantages of multidimensional chromatography and flow catalysis.