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Published on: October 18, 2019
A Simple Tetraminocalix[4]arene as a Highly Efficient Catalyst under "On-Water" Conditions through Hydrophobic
Margherita De Rosa1, Pellegrino La Manna1, Annunziata Soriente1
1Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno, Via Ponte don Melillo, 84084, Fisciano (SA), Italy.
Abstract:
The simple tetraminocalix[4]arene 1, which contains weak H-bond-donor NH2 groups, is reported to be a highly efficient organocatalyst for the Vinylogous Mukaiyama Aldol Reaction (VMAR) of 2-(trimethylsilyloxy)furan 5 with α-ketoesters 6 a-l under "on-water" conditions owing to the hydrophobic amplification of weak H-bond interactions. The catalytic efficiency of calixarene catalyst 1 was shown to be closely related to its recognition abilities towards the reactants 5 and 6 through a multipoint recognition model. The proposed model provided good explanations for the differences on the reaction rate acceleration and on the stereoselectivity observed with different substrates.
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