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On the Solvent and Temperature Driven Stereoselectivity of the Diels-Alder Cycloaddition Reactions of Furan with Maleic Anhydride and Maleimide

preprint
submitted on 19.12.2019 and posted on 23.12.2019 by Veejendra Yadav, Dasari L V K Prasad, Arpita Yadav, Kedar Yadav
In quantum chemical calculations, the Diels-Alder cycloaddition reaction of maleic anhydride with furan favors the endo-isomer kinetically in the gas phase. This preference, however, changes in favor of the exo-isomer on inclusion of solvent effects. For example, in acetonitrile, the exo-isomer was calculated to form twice as fast as the endo-isomer at room temperature, an observation that corroborates well with the experiments. The free energy change of the reaction is such that it allows faster reversal of the endo-isomer to the reactants in an equilibrium process and, thus, the predominance of the more stable exo-isomer eventually. The reaction of maleimide with furan is similar to that of maleic anhydride. However, it favors predominantly endo selectivity at temperatures below 320 K which is in excellent agreement with the experimental studies of temperature dependence of this DA reaction. Further, a gedanken calculation of the DA reaction of cyclopropene with furan has been investigated to delineate the effect of the retro-pathway on the stereoselectivity.

History

Email Address of Submitting Author

vijendra@iitk.ac.in

Institution

Indian Institute of Technology Kanpur

Country

India

ORCID For Submitting Author

0000-0001-8294-0677

Declaration of Conflict of Interest

There are no conflicts to declare.

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