Trisulfonated triphenylphosphine ligand salt

In order to keep the mild conditions, hydroxycarbonylation has been performed in biphasic media, maintaining the catalyst in the aqueous phase thanks to water-soluble mono- or diphosphine ligands. In the presence of the sodium salt of trisulfonated triphenylphosphine (TPPTS), palladium was shown to carbonylate efficiently acrylic ester [19], propene and light alkenes [20,21] in acidic media. For heavy alkenes the reduced activity due to the mass transfer problems between the aqueous and organic phases can be overcome by introducing an inverse phase transfer agent, and particularly dimeihyl-/-i-cyclodextrin [22,23]. Moreover, a dicationic palladium center coordinated by the bidentate diphosphine ligand 2,7-bis(sulfonato)xantphos (Fig. 2) catalyzes, in the presence of tolylsulfonic acid for stability reasons, the hydroxycarbonylation of ethylene, propene and styrene and provides a ca. 0.34 0.66 molar ratio for the two linear and branched acids [24],... 

Initially, only dipolar aprotic solvents such as dimethylformamide (DMF), N-methylpyrrohdinone (NMP), dimethyl sulfoxide (DMSO), acetonitrile (MeCN), and anisole were common (Table 8.2). However, the presence of water has been found to accelerate certain Heck reactions [82, 83], and consequently, the development has gone to water-soluble triarylphosphine ligands (e.g., triphenylphosphine-m-trisulfonic acid sodium salt (TPPTS) [56a]) with which many alkene arylations... 

In the course of introducing the immobilized ligand TPPTS (triphenylphosphine trisulfonate) on an industrial production scale it was found that cations, especially ammonium and ammonium derivatives, have an extreme influence on the properties of the TPPTS salts. Even slight variations within the cations have a tremen-... 

In addition to pyridinium based catalysts and cyclodextrin derivatives, some special compounds have also been reported to be useful inverse PT catalysts for specific reactions. Te-tramethyl ammonium salts that are ineffective as PT catalysts due to their high solubility in the aqueous phase have been found to be effective inverse PT catalysts in some systems. Some metal compounds like platinum, palladium, and rhodium can strongly complex with water-soluble ligands such as the trisodium salt of triphenylphosphine trisulfonic acid, and act as effective inverse PT catalysts. These complexes are soluble in the aqueous phase only and, thus are easily recov-... 

Sulfonated triphenylphosphine [TPPTS (triphenylphosphine, m-trisulfonated) tri(m-sulfophenyl)phosphine] (II-l) and monosulfonated triphenylphosphine [TP-PMS (triphenylphosphine, monosulfonated) 3-(diphenylphosphino)benzenesul-fonic acid] (II-2) are commercially available ligands and their sodium salts are water-soluble [15]. The Na salt of the ligand TPPTS is very soluble and may be too soluble in water, hence moderately soluble TPPMS is preferred. Another water-soluble phosphine is 2-(diphenylphosphinoethyl)trimethyl ammonium halide (II-11) [16]. A number of other water-soluble phosphines are now known (Table 1.2). Pd complexes, coordinated by these phosphines, are soluble in water, and Pd-catalyzed reactions can be carried out in water, which is said to have an accelerating effect in some catalytic reactions. 

Figure 15.1 Typical hydroformylation monophosphine ligands TPPTS (3, triphenylphos-phine trisulfonate, sodium salt), TPPTIM (4, triphenylphosphine trisulfonate, l-butyl-2,3-dimethylimidazolium salt), and TPPMS (5, triphenylphosphine monosulfonate, sodium salt).

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