Origin of the “endo rule” in Diels–Alder reactions
Article first published online: 25 NOV 2013
Copyright © 2013 Wiley Periodicals, Inc.
Journal of Computational Chemistry
Volume 35, Issue 5, pages 371–376, 15 February 2014
How to Cite
How to cite this article: J. Comput. Chem. 2014, 35, 371–376. DOI: 10.1002/jcc.23500, .
- Issue published online: 22 JAN 2014
- Article first published online: 25 NOV 2013
- Manuscript Accepted: 2 NOV 2013
- Manuscript Received: 1 NOV 2013
- Spanish MINECO. Grant Numbers: CSD2007-00006, CTQ2010-20714-C02-01
- Spanish CAM. Grant Number: S2009/PPQ-1634
- The Netherlands Organization for Scientific Research
- activation strain model;
- Alder reaction;
- endo rule;
- density functional theory calculations;
Detailed density functional theory calculations definitively rationalize the preference for the endo cycloadduct (also known as endo rule) in text-book thermal Diels–Alder reactions involving maleic anhydride and cyclopentadiene or butadiene. This selectivity is mainly caused by an unfavorable steric arrangement in the transition-state region of the exo pathway which translates into a more destabilizing activation strain. In contrast with the widely accepted, orbital-interaction-based explanation for the endo rule, it is found that neither the orbital interactions nor the total interaction between the deformed reactants contributes to the endo selectivity. © 2013 Wiley Periodicals, Inc.