Carbonyl allyl resonance energy

In terms of the mechanism, the activation energy for dj-methyl cinnamate (3, Table 10) should be lower than that of m-2-butene by about one benzyl resonance (/ benzyl — 13 kcal.mole ) and one carbonyl allyl resonance (5.8 kcal.mole" ). The corrected activation energy, obtained from the observed rate constant at T and the estimated z4-factor, is in reasonably good agreement with this expectation. Therefore, although the experimental parameters for m-methyl cinnamate are low, the rate coefficients are reasonably reliable. Such is not the case... 

The cyclic group Y(C6J) 0, where the carbonyl group is adjacent to the sp radical, is derived from the dissociation of Y(C6H6)=0 to Y(C6H5 )=0 (Y(C=CC=CC C-)=0) + H at 69.75 kcal moV VCJC OC C derived from CH2=CHCH(CH=0)C=CH to CH2=CHC (CH=0)C=CH + H, is 69.67 kcal mofboth have a similar bond energy about 69.7 kcal mof due to the double allylic resonance and the resonance with the carbonyl group. 

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