Triphenylphosphine trisulfonate

Much emphasis has been placed in recent times on easily recoverable liquid bi-phasic catalysts, including metal clusters in nonconventional solvents. For instance, aqueous solutions of the complexes [Ru3(CO)12.x(TPPTS)x] (x=l, 2, 3 TPPTS = triphenylphosphine-trisulfonate, P(m-C6H4S03Na)3) catalyze the hydrogenation of simple alkenes (1-octene, cyclohexene, styrene) at 60°C and 60 bar H2 at TOF up to 500 h 1 [24], while [Ru i(CO)C (TPPMS) >,] (TPPMS = triphenylphos-phine-monosulfonate, PPh2(m-C6H4S03Na) is an efficient catalyst precursor for the aqueous hydrogenation of the C=C bond of acrylic acid (TOF 780 h 1 at 40 °C and 3 bar H2) and other activated alkenes [25]. The same catalysts proved to be poorly active in room temperature ionic liquids such as [bmim][BF4] (bmim= Tbutyl-3-methylimidazolium). No details about the active species involved are known at this point. 

The use of water-soluble metal catalysts for the hydrogenation of thiophenes in aqueous biphasic systems has been primarily introduced by Sanchez-Delgado and coworkers at INTEVEP S.A. [61]. The precursors RuHC1(TPPTS)2(L2) (TPPTS=triphenylphosphine trisulfonate L=aniline, 1,2,3,4-tetrahydroquinoline) and RuHC1(TPPMS)2(L2) (TPPMS=triphenylphosphine monosulfonate) were... 

Sinou and co-workers also studied the allylation of uracil 190 and thymine 191, but in an aqueous solvent (water/acetonitrile in a ratio 17/2) and in the presence of trisodium triphenylphosphine trisulfonate (tppts, 199) as water-soluble phosphine. Their results are summarized in Table VI. Cinna-myl acetate was used with one equivalent of diazabicycloundecene (DBU) as a base instead of mixed carbonate. Under these conditions, good regiose-lectivities at N-l (to 193 and 185) were observed, as well as lack of diallyla-tion products for uracil and thymine, even with an excess of cinnamyl acetate. It seems that the nonformation of diallylated products is related to the precipitation of the N-l isomers 193 and 185 in the aqueous medium (94TL7085). 

TPPTS triphenylphosphine trisulfonate, tri-sodium salt P(C6H4S03Na)3... 

Subsequently, water-soluble catalysts have been developed for use in aqueous biphasic systems. One such catalyst precursor is RuHCl(TPPTS)2(L)2 (where TPPTS = triphenylphosphine trisulfonate and L = aniline or a similar base). 

Fig. 2 Fast evaluation of a new catalyst capability reduction of benzaldehyde (BZA) in benzylic alcohol (BZOH) by sodium formate catalyzed by a ruthenium-triphenylphosphine trisulfonated sodium complex. Twenty Tmoles BZA were injected. Seventeen Tmoles BZOH were formed (85% conversion). A 59-mL CCC machine, Vs = 52 mL of 5M sodium formate aqueous solution, = 7 mL cyclohexane at 1.5 mL/min in the ascending tail to head direction, 750 rpm. (From Ref. 5.)...

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-... 

Figure 1. Influence of cations on the properties of TPPTS salts. Triphenylphosphine trisulfonate.

Two-Phase Hydroformylation of Higher Alkenes with Rhodium/Triphenylphosphine Trisulfonate (TPPTS) as Catalyst System... 

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-... 

An early example of a mesoporous-supported rhodium catalyst is that based on controlled pore glass in which there is a shapely defined pore size of ca. 24 A.163 Impregnation of such a glass with HRu(CO)(TPPTS)3 (TPPTS = triphenylphosphine trisulfonate) gives a catalyst with activity in hydroformyla-tion reactions ... 

An indication of the significance of the process as far as the scientific world is concerned is the fact that the standard ligand for aqueous two-phase catalysis, triphenylphosphine trisulfonate (TPPTS), now appears in the Aid-rich Catalogue of Fine Chemicals. The elegant approach to catalyst separation has in turn led to intense preoccupation with possible laboratory and industrial applications of two-phase catalysis, as well as extension of the process into new areas. A series of important contributions to the literature has recently cast a rather bright spotlight in this direction. 

A new, water soluble palladium catalyst was used in the Sonogashira reaction (Pd(OAc)2 triphenylphosphine-trisulfonate sodium salt) [131], and several groups adapted the Sonogashira coupling and subsequent cyclization to the solid-phase synthesis of indoles. Bedeschi and coworkers used this method to prepare a series of 2-substituted-5-indolecarboxylic acids [132], CoUini and Ellingboe extended the technique to l,2,3-trisubstituted-6-indolecarboxylic acids [133]. Zhang and... 

A high-pressure NMR study revealed that the solution structure of [RhH( GO)(TPPTS)3] (TPPTS = triphenylphosphine trisulfonate) in [G4GiIm]BF4 is similar to that of [RhH( GO)(PPh3)3] in toluene- s at elevated syngas pressures. 

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).

The in situ formation of Pd(0) complexes takes place when Pd(OAc)2 is associated with various phosphines (i) aromatic phosphines (p-Z—C6H4)3P (Z = EDG or EWG). The formation of the Pd(0) complex follows a Hammett correlation with a positive slope [20]. The more electron-deficient the phosphine, the faster the reduction process this is in agreement with the intramolecular nucleophilic attack of the acetate onto the ligated phosphine as proposed in Scheme 1.13 (ii) aliphatic phosphines [20] (iii) water-soluble phosphines, triphenylphosphine trisulfonate (trisodium salt) [25] and triphenylphosphinetricarboxylate (trilithium salt) [26]. One major exception is the tri-o-tolylphosphine P(o-Tol)3, which cannot reduce Pd(OAc)2 to a Pd(0) complex in DMF or THE. Instead, an activation of one C-H bond of the tolyl moieties by Pd(OAc)2 takes place, leading to a dimeric P,C-palladacycle (see Section 1.5), as reported by Herrmann et al. in 1995 [27]. Such a Pd(ll) P,C-palladacycle catalyses Mizoroki-Heck reactions [27]. It is, however, a reservoir of a Pd(0) complex, as recently established by d Orly6 and Jutand [28] in 2005 (see Section 1.5). 

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