Towards the Development of a Selective Ruthenium‐Catalyzed Hydroformylation of Olefins

Abstract

The ruthenium-catalyzed hydroformylation of 1- and 2-octene to give preferentially the corresponding linear aldehyde is reported. The catalyst system comprising of Ru3 (CO)12 and an imidazole-substituted monophosphine ligand allows for high chemo- and regioselectivity. The hydroformylation proceeds with unprecedented rates for a ruthenium-based catalyst.

In Situ FTIR and NMR Spectroscopic Investigations on Ruthenium‐Based Catalysts for Alkene Hydroformylation

“…[20] Reaction rates are lower for 3,3-dimethyl-1-butene compared with 1-octene, which was used as substrate in the aforementioned study. [20,67] The same relative trend in activity was found as observed for toluene as solvent:t he system Ru/L2 showedt he highest activity followed by Ru/L3 and then Ru/L1 (cf. Ta ble 1).…”

“…[20] inferiorr esultsw ere noted when the cyclohexyl groups of ligandsw ere substituted by tert-butyl or adamantyl groups.T he yields of aldehydesc ollapsed almostc ompletely. Furthermore, when a2 -pyrrolyl group was incorporatedi nstead of the 2-imidazolyl unit, as ignificant loss in activity was observed.…”

“…Selectedmonophosphines for which comparatively lowa ctivities in hydroformylation werefound in Ref. [20]. …”

“…[20] No significant change in linearity was observed for as eries of ligandsw ith differents ubstituents on the imidazolyl moiety. Notably,n o pronounced variation in activity was observed.…”

“…[20] The interpretation of IR spectra is supported by vibrational analysis through DFT calculations. Catalysts with different ligands were selected in order to correlate their catalytic performance with spectroscopic features.…”