DMAP-based flexible polymer networks formed via Heck coupling as efficient heterogeneous organocatalysts

Polymeric Networks Containing Amine Derivatives as Organocatalysts for Knoevenagel Reaction within Continuously Driven Microfluidic Reactors

The Knoevenagel reaction is a classic reaction in organic chemistry for the formation of C-C bonds. In this study, various catalytic monomers for Knoevenagel reactions were synthesized and polymerized via photolithography to form polymeric gel dots with a composition of 90% catalyst, 9% gelling agent and 1% crosslinker. Furthermore, these gel dots were inserted into a microfluidic reactor (MFR) and the conversion of the reaction using gel dots as catalysts in the MFR for 8 h at room temperature was studied. The gel dots containing primary amines showed a better conversion of about 83–90% with aliphatic aldehyde and 86–100% with aromatic aldehyde, compared to the tertiary amines (52–59% with aliphatic aldehyde and 77–93% with aromatic aldehydes) which resembles the reactivity of the amines. Moreover, the addition of polar solvent (water) in the reaction mixture and the swelling properties of the gel dots by altering the polymer backbone showed a significant enhancement in the conversion of the reaction, due to the increased accessibility of the catalytic sites in the polymeric network. These results suggested the primary-amine-based catalysts facilitate better conversion compared to tertiary amines and the reaction solvent had a significant influence on organocatalysis to improve the efficiency of MFR.

Isolation of a stable pyridine radical anion

For almost 150 years, pyridine radical anions have been described as elusive transient species that cannot be isolated due to dimerization and/or subsequent decomposition reactions. In this work the first example of a stable pyridine radical anion is presented.

Pillar[5]arene-based chiral 3D polymer network for heterogeneous asymmetric catalysis

We report the preparation of a chiral 3D polymer network endowed with ability of heterogeneous asymmetric catalysis and good recyclability based on pillar[5]arene and (R,R)-tetraaryl-1,3-dioxolane-4,5-dimethanol derivatives.

4-Dialkylaminopyridine modified magnetic nanoparticles: as an efficient nano-organocatalyst for one-pot synthesis of 2-amino-4H-chromene-3-carbonitrile derivatives in water

A new DMAP-based magnetic nano-organocatalyst was developed for efficient one-pot synthesis of 2-amino-4H-chromene-3-carbonitrile derivatives in water as a green solvent.