Correlation of Relative Rates of PdCl₂ Oxidation of Functionalized Acyclic Alkenes versus Alkene Ionization Potentials, HOMOs, and LUMOs

Abstract

Investigations of the title reaction, carried out by plotting logs of the relative reaction rates vs IPs, vs HOMOs, and vs LUMOs, reveal multiple nearly parallel lines of correlation with small negative slopes in each. Overall, the natural grouping into monosubstituted and disubstituted alkenes gives better correlations than that obtained by using all alkenes. Comparison with analogous plots for other reactions indicates that the mechanism for this reaction has similarities to that for hydroboration, the major difference being that the lines in the plots for hydroboration have positive slopes, indicating an electrophilic rate-determining step involving the pi electrons, while those for the title reaction have small negative slopes, indicating a nucleophilic rate-determining step. Of the two reaction mechanisms proposed for the title reaction, only one has a nucleophilic attack at the complexed alkene as the rate-determining step, and therefore, this work supports that reaction mechanism.

Challenges in modelling homogeneous catalysis: new answers from ab initio molecular dynamics to the controversy over the Wacker process

“…11 As already commented in the previous section, correlation between reaction rates with ionization potentials and HOMO and LUMO energies on a series 85 of alkenes, was interpreted by the authors as a support for the syn addition.…”

First evidence for the use of polyamines as nucleophiles in a regioselective palladium-catalyzed allylic amination reaction

“…Furthermore, due to the steric hindrance around the palladium in C compared to A, C is likely to be a very small component in the equilibrium. Moreover, the strength of the palladium/ olefin interaction in complex D is higher than that in complex E due to increased degree of substitution in E. 13 In this context, ionization of complex D should be more facile than complex E leading preferentially to the formation of the thermodynamic linear product. Otherwise, the presence of the kinetic adduct could be also rationalized though the formation of the s-palladium complex A, which could be susceptible to a nucleophilic attack proceeding in an S N 2 0 fashion at the more substituted terminus and leading to the branched allylic polyamine.…”

“…The reflux is maintained for 1 h. After cooling to room temperature, the solvent is removed under reduced pressure and the crude product is purified by column chromatography (silica gel; CH 2 Cl 2 /MeOH/NH 4 OH, 7:3:1) affording a clear oil of Z-3 in 80% yield. 13 …”

“…MS (ESI) C 14 H 32 N 4 m/z 257.2700 (100%, (MþH þ )).4.2.6. {3-[Bis-(3-amino-propyl)-amino]-propyl}-bis-(3-methyl-but-2-enyl)-amine(13) 1. H NMR (MeOD, 300 MHz): d¼5.29 (t, J¼5.3 Hz, 2H), 3.11 (d, J¼5.3 Hz, 4H), 2.70 (t, J¼7.0 Hz, 4H), 2.44e2.56 (m, 8H), 1.78 (s, 6H),1.69 (s, 6H),1.62e1.72 (m, 6H).…”

Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation

“…Thus, plotting log k rel values against IEs or HOMO energies of alkenes allows a comparison of the significance of steric and electronic effects in the rate-determining step of the reaction. In particular, additions to alkenes, that proceed via 3-membered intermediates (or transition states), display plots with one trend line if the reaction rate is predominantly dependent upon electronic effects [72–76], and multiple trend lines if both steric and electronic effects are important [72–73 77–78]. In this work, we apply these established relationships for a detailed analysis of the steric and electronic effects in the addition of PhSeCl to a series of representative alkenes and compare these findings with the corresponding data reported for the analogous sulfenylation reactions.…”