A DFT investigation of base-catalyzed β-elimination reactions in water solution for systems activated by the pyridine ring: Theory vs. experiment

We report a theoretical investigation of β-elimination reactions in systems activated by the pyridine ring. The investigated reaction, the acetohydroxamate-induced β-elimination in protonated N-[2-(2-pyridyl)ethyl]quinuclidinium, offers a unique opportunity to test computational methodologies since detailed kinetic experimental data are available. We calculated the pKas of the acetohydroxamic acid and the substrate and thoroughly characterized the reactive free-energy profile. The reaction proceeds via a stable carbanion intermediate. Except a discrepancy in the reproduction of the pKa of the acetohydroxamic acid, the calculated free-energy profile is in excellent agreement with the experiment, showing the general reliability of the present approach.