We report a theoretical investigation of beta-elimination reactions in systems activated by the pyridine ring. The investigated reaction, the acetohydroxamate-induced beta-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 pK(a)s 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 pK(a)s of the acetohydroxamic acid, the calculated free-energy profile is in excellent agreement with the experiment, showing the general reliability of the present approach. (C) 2008 Elsevier B. V. All rights reserved.
A DFT investigation of base-catalyzed beta-elimination reactions in water solution for systems activated by the pyridine ring: Theory vs. experiment
De Angelis F;Sgamellotti A;
2008
Abstract
We report a theoretical investigation of beta-elimination reactions in systems activated by the pyridine ring. The investigated reaction, the acetohydroxamate-induced beta-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 pK(a)s 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 pK(a)s of the acetohydroxamic acid, the calculated free-energy profile is in excellent agreement with the experiment, showing the general reliability of the present approach. (C) 2008 Elsevier B. V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
