The catalytic effect of various Lewis acids (LAs) on the ene reaction between propene (ene) and but-3-en-2-one (enophile) was studied quantum chemically using density functional theory and with coupled-cluster theory. The studied LAs efficiently accelerate the ene reaction by lowering the reaction barrier up to 12 kcal mol−1 compared to the uncatalyzed reaction. Our detailed activation strain and Kohn-Sham molecular orbital analyses reveal that coordination of a LA catalyst to the enophile decreases the reaction barrier of the ene reaction by inducing an asymmetry in the π-electronic system, which increases the asynchronicity and hence relieves the otherwise highly destabilizing activation strain and Pauli repulsion between the closed-shell filled π-orbitals of the ene and enophile. In all, these findings further demonstrate the generality of the Pauli-lowering catalysis concept.
|Number of pages||9|
|Journal||European Journal of Organic Chemistry|
|Early online date||12 Sep 2021|
|Publication status||Published - 7 Oct 2021|
Bibliographical noteFunding Information:
This work was supported by the Netherlands Organization for Scientific Research (NWO) and the Dutch Astrochemistry Network (DAN).
© 2021 The Authors. European Journal of Organic Chemistry published by Wiley-VCH GmbH
Copyright 2021 Elsevier B.V., All rights reserved.
- Activation strain model
- Density functional calculations
- Ene reaction
- Lewis acids