Notes on acetal formation in stereoselective hydrogenation of methyl-3-oxobutyrate on Ru–BINAP chiral complex

Kinetic Study of the Asymmetric Hydrogenation of Methyl Acetoacetate in the Presence of a Ruthenium Binaphthophosphepine Complex

“…As a result of our kinetic studies and the comparison of the experimental data with different kinetic models we conclude that the literature proposed reaction network for the hydrogenation of MAA in methanol with Ru-BINAP complexes [15] differs from our Ru-phenylphosphepine-catalysed reaction network. The here proposed reaction network of model 6 shows a much better fit to the experimental data and explains easily the experimental fact that the asymmetric hydrogenation of MAA is significantly accelerated in alcoholic solvents.…”

“…The residual of model 5 was determined as 0.257, the calculations based on model 6 resulted in a residual of 0.215. To illustrate the difference in the fit quality between the formal reaction network similar to the literature [15] (model 1) and the expanded models tested in this work, Figure 7 shows the parity plots of the MHB formation for models 1 and 6 in comparison. All parity plots based on model 6 show the best agreement of experimental and modelled data for the reactants.…”

“…Obviously, these parallel reactions are reversible equilibrium reactions. Figure 2 shows the formal reaction scheme as it was known from the literature [15] when we started the detailed kinetic studies described in this publication.…”

“…Formal reaction scheme of MAA hydrogenation similar to ref. [15] Results and Discussion Determination of the Reaction Network Figure 3 shows the concentration profiles of all liquid reactants during a typical hydrogenation experiment (more experimental data including reproduction runs and hydrogenation runs at different temperatures and pressures can be found in the Supporting Information). The results of the kinetic modelling (discussed in detail in the section "Estimation of Kinetic Parameters" below) are indicated as dotted lines.…”

“…As a first benchmark, the proposed reaction scheme [15] was adapted for its utilisation as a kinetic reaction network. In this adaption, all reaction steps including experimentally non-detectable intermediates (namely Int 1 and Int 2 from Figure 2) were omitted.…”