Kinetic and thermodynamic study of substituent effect on the Claisen rearrangement of para-substituted SI aryl ether: a Hammett study via DFT

Subject Areas : Journal of Physical & Theoretical Chemistry

S. R. Emamian ¹ , M. R. Zardoost ² , K. Zare ³ , E. Zahedi ⁴ , H. Aghaie ⁵

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Received: 2015-05-23 Accepted : 2015-05-23 Published : 2009-11-01

Keywords: Hammett, Density functional theory, Substutuent effect, Claisen re, Ally! aryl ether,

Abstract :

In order to find the susceptibility of the Claisen rearrangement and next proton shift reaction of ally) aryl etherto the substiment effects in pan position, the kinetic and the:rmodynamie parameters are calculated at The33 LTP level using 6-3110. b asis set. The calculated activation energies for the rearrangements and protonshift reactions are around 3133 kcaUmol and 52.16 kcal/mol, nap.. lively. Negative values for the activationentropy confirm the concerted mechanign for the Claisen rearrangement and proton shift reaction. TheHammett p value of -1.3433 obtained in Claigen rearrangement. Negative Hammett p value indicate, that theelectron donating groups slightly increase the rate of Claisen rearrangement. Positive Hammett p value (2.5132)for proton shift reaction indicates that electron withdrawing coups increase the rate of reaciion.