engleski

Determination of nucleofugalities for benzoates based on theoretical model

Solvolytic reactivities of some substituted benzoates in various solvents have been determined experimentally in the terms of nucleofugalities (Nf) according to the Mayr’s LFER equation log k (25 °C) = sf (Nf + Ef). A quantum-chemical model reaction based on the heterolytic dissociation of 2-oxyethyl benzoates has been developed for determining the reactivity of a vast number of benzoates. Experimentally determined ΔG‡ of 13 dianisylmethyl benzoates for solvolysis in 80% ethanol have been correlated with ΔH‡ of the model epoxy ring formation, calculated by DFT quantum-chemical method in the presence of the IEFPCM solvation model. Along with the excellent correlation (r = 0.997), very good agreement between the experimentally derived Nf parameters and calculated Nf parameters have been observed. The method for calculating the nucleofugalities of substituted benzoates, which includes this theoretical model, has been established, ultimately providing a possibility for determining the solvolytic SN1 reactivity for any benzoate in a given solvent.

benzoates; nucleofugality; reactivity; kinetics; dft; pcm

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