Sreekumar, Krishnapillai; Rajesh Krishnan, G(Eur. J. Org. Chem, August , 2008)
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Abstract:
This paper describes the first use of polystyrene-supported
poly(amidoamine) (PAMAM) dendrimers as heterogeneous
basic organocatalysts for carbon–carbon bond formation.
Polystyrene-supported PAMAM dendrimers of first, second
and third generations have been used as reusable base catalysts
in Knoevenagel condensations of carbonyl compounds
with active methylene compounds. The reactions proceed in short periods of time and with 100% selectivity. This novel
catalyst eliminates the use of aromatic and halogenated solvents,
as well as complex purification processes. The catalysts
can be recycled ten times.
This manuscript describes the first example of silver ion complex of a dendritic tetranitrile ligand catalyzed
one-pot three component Mannich reaction and 1,5-benzodiazepine synthesis. The catalyst can be separated from the
products by a change in the solvent. The catalyst is reusable.