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Updated: May 22, 2025

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Organocatalyzed Diels-Alder Reactions: Unexplored Hydrogen Bond Donor Catalysts
Eveline H Tiekink1, Ron Verdijk1, Trevor A Hamlin1
1Department of Chemistry and Pharmaceutical Sciences, AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The, Netherlands.
Abstract:
We have quantum chemically investigated the catalytic effect of hydrogen bonding organocatalysts, (H2N)2C=X (X=O, S, Se, NH, PH, AsH, CH2, SiH2 GeH2), such as urea, on the classic Diels-Alder reaction. All studied hydrogen bond donor catalysts enhance the Diels-Alder reaction between acrolein and 1,3-butadiene to a similar extent. Our activation strain and Kohn-Sham molecular orbital analyses show that these organocatalysts lower the reaction barrier by polarizing the π-orbitals away from the reactive carbon atoms of acrolein, reducing the Pauli repulsion between the reactants. Interestingly, this catalytic mechanism is not limited to >C=X moieties with relatively electronegative X (e. g., O, S, NH) but extends to situations like >C=CH2 and even >C=SiH2.
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