Palladium-catalysed methoxycarbonylation of ethene with bidentate diphosphine ligands: a density functional theory study

Abstract

Catalytic methoxycarbonylation of ethene with a bidentate tertiary phosphine (DTBPX) and palladium has been explored at the B3PW91-D3/PCM level of density functional theory. Three different pathways for formation of methyl...

Computational modelling of Pd-catalysed alkoxycarbonylation of alkenes and alkynes

“…Here we have added an example of the possible mechanistic pathways from our recent work on methoxycarbonylation of ethene. 98 The alkoxy cycle begins with the migratory insertion of CO to the Pd-OMe bond followed by insertion of alkene into the ester functionality with alcoholysis as the final step (Scheme 3A). The hydride cycle operates via a Pd-H complex, which begins with an a,b alkene insertion, followed by an a,a insertion of the alkyl group into coordinated CO closing at the alcoholysis step (Scheme 3B).…”

“…Their methanolysis barriers with similar schemes turned to be much lower than those we recently published for a different system. 98 These low barriers come from further destabilisation of the Pd-acyl complex due to greater steric bulk on the phosphines; however, off-cycle intermediates appeared to be the MARIs. In this study the MHP scheme 87 was found to be crucial to account for the extent of reversibility of individual reaction steps, in order to account for the observations from deuterium labelling studies.…”

“…We recently studied Pd-catalysed methoxycarbonylation of ethene with bidentate diphosphine ligands at the B3PW91-D3/ SDD/6-311+G**/PCM//B3PW91/SDD/6-31G** level of theory using methanol as the model solvent. 98 We use the same methodology in all work from us presented in this perspective. We explored three pathways, (i) carbomethoxy pathway, (ii) ketene pathway, and (ii) hydride-hydroxyalkylpalladium pathway.…”

“…The ligand DTBPX, is shown in Scheme 1(i). Reprinted from ref 98. (Copyright 2020 Royal Society of Chemistry).…”

Ferrocenylmethylphosphanes and the Alpha Process for Methoxycarbonylation: The Original Story

“…Thus, we have even more confidence that the ligands described in this paper are worthy of much deeper investigation, as are the new ligands under development within our group. A recent DFT study may help advance the mechanistic insights of this process [78]. Further synthetic details of in situ methods for phosphane preparation can be found in the Supplementary Materials.…”