Rh-catalyzed linear hydroformylation of styrene

Abstract

Usually the Rh-catalyzed hydroformylation of styrene predominantly yields the branched, chiral aldehyde.An inversion of regioselectivity can be achieved using strong π-acceptor ligands. Binaphthol-based diphosphite and bis(dipyrrolyl-phosphorodiamidite) ligands were applied in the Rh-catalyzed hydroformylation of styrene. High selectivities up to 83% of 3-phenylpropanal were obtained with 1,1-bi-2-naphthol-based bis(dipyrrolyl-phosphorodiamidite) with virtually no hydrogenation to ethyl benzene. The coordination chemistry of those ligands towards Rh(I) was investigated spectroscopically and structurally.

Rhodium/bisphosphite catalytic system for hydroformylation of styrene and its derivatives

“…It had been proved that the rhodium bisphosphine complexes bearing large bite angle and containing more electron-withdrawing groups would further improve the regioselectivity of linear aldehydes in the hydroformylation of olefins. [14][15][16] The electronic effects in the hydroformylation of styrene have been systematically investigated by Vogt and co-workers, [17] but the steric properties also played an important role in styrene hydroformylation. Herein, we reported the influence of steric properties through comparing ligands containing different backbones.…”

Selective hydroformylation of alkyl acrylates using [2,2′-bis(dipyrrolylphosphinooxy)-1,1′-(±)-binaphthyl]/Rh catalyst: reversal of regioselectivity

“…As the hydroformylation reaction highly relies on the reaction condition, the inuence of P/Rh ratio, temperature, and pressure on regioselectivity was evaluated. The rhodium catalyst was prepared in situ by mixing the ligand L1 with Rh(acac)(CO) 2 (acac ¼ acetylacetonate) in toluene. The reaction proceeded in toluene and was analyzed by gas chromatography (GC).…”

“…The hydroformylation reaction was performed in a 60 mL steel autoclave equipped with a pressure gauge, a magnetic stirrer and a thermocouple. The substrate alkyl acrylate (1.0 mL) was mixed with a toluene solution, which containing Rh(acac)(CO) 2 (1 mmol, 260 mL) and ligand (5 mmol). Then, the autoclave was sealed and purged with syngas (CO/H 2 ) over three times and subsequently pressurized to a preset value and started to stir.…”

“…Recently, researchers have developed a consuming passion for the hydroformylation of functionalized olens, like styrene, 1,2 dicyclopentadiene, [3][4][5] vinylacetate, 6 allyl alcohol, 7,8 alkyl acrylate [9][10][11][12] and so on. Hydroformylation of alkyl acrylate could provide 1,3-and 1,4-bifunctional carbonyl compounds (corresponding to branched and linear aldehydes), and these compounds could transform to malonic acids, 1,4-dicarboxylic acid, lactones, 2-methyl-1,3-propanediol and 1,4-butanediol 13,14 (shown in Scheme 1), which are useful intermediates for the production of ne chemicals, pharmaceuticals, resin, adhesives, oil paints, plasticizers and so on.…”

“…9,12 A number of approaches have been adopted to improve the activity, like using supported aqueous-or ionicphase catalyst, 19 or conducting the hydroformylation in supercritical CO 2 . 10,11 In addition, the hydroformylation generally gave the branched aldehyde as the major product.…”