Rhodium‐Catalyzed Hydroformylation Using Hindered Phosphine Ligands: An In Situ Study

Abstract

Ligands behaving badly: A series of hindered biaryl phosphine compounds are used as ligands in rhodium‐ catalyzed hydroformylation. In situ analysis of the resultant catalysts under operating conditions shows that the ligands are dissociated under high pressures of syngas, thereby creating an unselective rhodium catalyst for the hydroformylation.

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

“…Styrene (>99%) was redistilled prior to use and other reagents were of analytical grade. Rh(acac)(CO) 2 [21] and ligands were prepared according to the literature and their structures were confirmed by comparing their 1 H, 13 C and 31 P NMR spectra with the literature. [16,[18][19][20]22] Synthesis of Dipyrrolyl(naphthalene-2-yloxy)phosphine (6) Synthesis of 6 was according to the literature.…”

“…[12] These ligands with strongly electron-withdrawing groups result in lower electron density around the rhodium metal and this in turn weakens the metal-carbonyl bond, which is favorable for the dissociation of CO, and thereby accelerates catalysis. [13] Ligand (III) also has a highly Lewis acidic phosphorus atom leading to the highest L/B ratio. 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.…”

Influence of electrostatic repulsive force and electron-withdrawing effect in ionic diphosphine on regioselectivity of rhodium-catalyzed hydroformylation of 1-octene

“…Mononuclear rhodium complexes are the most efficient catalysts for this reaction and a great deal of work has been devoted to the improvement of reaction rates and selectivity by ligand design [1][2][3][4][5][6][7][8][9]. The n-regioselectivity of the catalyst can be enhanced by incorporation of sterically demanding substituents in the organic backbone of the ligands.…”

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

“…L1/Rh and L2/Rh exerted much better performance towards the conversion and the regioselectivity than other L/Rh system, probably as a result of the easy carbon monoxide dissociation owing to bearing the electron withdrawing N-pyrrolyl, and in turn facilitated the alkene coordination to metal. 34,35 In a word, the transformation of 1 to 2 was accelerated by the withdrawing N-pyrrolyl moiety. L1/Rh resulted in higher selectivity to linear aldehyde than L2/Rh at high temperature.…”

“…To verify it, the hydroformylation of ethyl acrylate using ligand L1 under low temperatures (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) C) was also performed and the results were shown in Table 2. Similar to the manner under 100 C, the reaction did not take place without ligand (entry 1).…”