DFT mechanistic investigation of the 1,2‐reduction of α,β‐unsaturated ynones

Abstract

The reaction mechanism of the phosphane catalyzed chemoselective 1,2-reduction of ynones using pinacolborane has been explored computationally. Numerous plausible reaction routes were investigated, and calculations based on density function theory showed that the hydride transfer to the vinylphosphonium cations in the catalytic cycle leads to dead-ends. The in situ formed dioxaborolane acts as the hydride donor and the reaction proceeds on a parallel path. Alternative mechanisms have also been examined alongside the crucial role of theoretical levels, moreover, the effect of a solvent was taken into consideration by applying the implicit polarizable continuum model.

Three-Component Reaction of 3-Formyl-6-Methylchromone, Primary Amines, and Secondary Phosphine Oxides: A Synthetic and Mechanistic Study

“…On the other hand, it should be mentioned that the utilization of electronic energies was chosen on purpose, as these values were shown to be the most robust and reliable. 26 In order to minimize the effect of the entropy (caused by the molecular number changes during reactions), the Van der Waals complex of the two investigated molecules was calculated and he energy of this complex was used during the evaluation of reaction energies and activation barriers. 1a and 2a (and their derivatives) were calculated with ethyl substituents at the nitrogen atoms (instead of the n -butyl) to reduce the computational time.…”

“…As the molecular number changes during reactions, the Gibbs free energies should be considered to describe the thermodynamic and kinetic profiles of these processes. On the other hand, it should be mentioned that the utilization of electronic energies was chosen on purpose, as these values were shown to be the most robust and reliable . In order to minimize the effect of the entropy (caused by the molecular number changes during reactions), the Van der Waals complex of the two investigated molecules was calculated and he energy of this complex was used during the evaluation of reaction energies and activation barriers.…”