Accurate prediction of experimental free energy of activation barriers for the aliphatic-Claisen rearrangement through DFT calculations

► DFT methods to predict free energy of activation values for aliphatic-Claisen desired. ► We benchmark calcd. free energy of activation barriers against 8 experimental values. ► Computed heavy KIE values were also benchmarked against experimental values. ► Found methods to adequately predict TS geometry for reaction of allyl vinyl ether. ► Found DFT methods to predict experimental ΔG‡ values to sub-kcal/mol accuracy.