Rhodium catalyzed deuteroformylation of styrene: (E)- and (Z)-β-deuterostyrene and β,β-dideuterostyrene formation via selective β-hydride elimination from the branched alkylrhodium intermediate

The kinetics of gas-phase propene hydroformylation over a supported ionic liquid-phase (SILP) rhodium catalyst

“…The decrease in the n/i ratio at high temperature is due to a shift in the equilibrium from the thermodynamically favorable primary alkyl complex [33] to the less favorable secondary alkyl complex. Our results are consistent with previous deutroformylation studies that found that Rh-alkyl formation is irreversible at low temperature but is reversible at higher temperatures [34,35].…”

Amino‐phosphanes in RhI‐Catalyzed Hydroformylation: New Mechanistic Insights Using D2O as Deuterium‐Labeling Agent

“…[22,37,38] Reversible 2,1 styrene insertion has previously been evidenced for hydroformylation experiments carried out under D 2 with Rh 4 (CO) 12 as the catalyst (without phosphane ligands) or with [Rh(acac)(CO) 2 ] in the presence of the mono-, diphosphane, or (R,S)-binaphos ligand. [21,23,37,38] With the latter Rh-binaphos catalytic system, the amount of α-plus β-D 1 -styrene was observed to increase significantly from 2 to 30 % when the syngas pressure was increased from 1 to 100 atm. Our results indicate that the styrene insertion becomes less reversible in the presence of phosphane ligands, with the exception of run 4.…”

“…The latter leads to quite comparable results to those of run 1 and to those of the process conducted with tetranuclear rhodium precatalysts in the absence of phosphane ligands. [38] In other previous work based on the use of mono or di-phosphane ligands, the amount of deuterium label found in styrene was reported to be very minor and to vary only slightly (from 0.1 to a few %) as a function of the phosphane nature. [21] The unusually high proportion of β-d 2 in run 4 could be due to a ligand dissociation, but we have no further evidence to confirm or refute this assumption at this time.…”

Regioselectivity in Hydroformylation of Aryl Olefins Using Novel Rhodium Polyether Phosphinite Catalysts

“…With further increase in temperature to 100°C, 3-phenyl propanal was obtained as a major product. This reversal of selectivity toward linear aldehyde in styrene hydroformylation is attributed to b-hydride elimination from branched Rh-alkyl intermediate resulting in higher linear product as explained by Lazzaroni et al [19,20] with the help of deuteroformylation experiments. Similar result is obtained with other phosphinite ligands DPPPEG-200, DPPPEG-600 and Bu(OPPh 2 ) 2 , as these ligands have Reaction conditions: Styrene = 10 mmol, Toluene = 20 mL, Reaction time = 4 h, 800 rpm a Chemoselectivity, molar ratio of aldehyde product to total reaction product similar steric and electronic properties with that of DPP-PEG-400.…”