Triphenylphosphine, reaction with organic

Neutral tris(dithiolene) complexes M(tdt)3 (M = Re, Mo, Tc) undergo drastic color changes when dissolved in polar solvents. Similar color changes also occur in the reactions with organic bases such as triphenylphosphine or o-phenanthroline (108). The reactions can be interpreted as one-electron reduction of the dithiolene complexes by the solvent or the base (Eq. 12). 

The use of other phosphorus-sulfur reagents for heterocyclic synthesis appears rare. It would be interesting to investigate in more detail the reaction of compounds, such as the phosphine sulfides, with organic substrates. Triphenylphosphine sulfide is an effective sulfur transfer agent, as it converts oxiranes into thiiranes in good yield. The reaction proceeds with retention of configuration.128... 

The first anionic polymetallayne of gold(I), P83, was prepared in moderate yield (36%) from the reaction of PPN[Au(acac)2] (PPN = bis(triphenylphosphine)iminium) with 1,3-diethynylbenzene in a 1 1 stoichiometric ratio.104 It was characterized by IR and H NMR spectroscopies. More interestingly, efforts were made to make two novel anionic heteronu-clear Pt(II)-Au(I) cr-acetylide polymers exhibiting both the linear (P84) and branched (P85) forms, but these polymers possessed very poor solubility in all common organic solvents.105... 

One approach to separation of the peroxides involves the precolumn reaction with MTS described in Section lll.D.l, with subsequent separation of the products by HPLC and standard ultraviolet detection at 225 nm. Separation of the H2O2 in the sample is accomplished by precolumn reaction with triphenylphosphine (TPP) and postcolumn detection of the oxidation product, triphenylphosphine oxide (TPPO). A nucleosil C8 reversed-phase column (70 X 3 mm, 5 /rm particle size) was used with acetonitrile-water gradient elution (40 to 75 to 40%) at a flow rate of 1 ml min to separate the products. Because the reaction with MTS precedes separation, this method gives a measurement of total organic peroxides. 

Synthesis of phosphonium salts Using a domestic oven it was shown that the reaction of triphenylphosphine and an organic halide is very rapid under the action of microwave irradiation. The reaction times were reduced to only few minutes in contrast with conventional heating, which requires from 30 min to 14 days [136], Temperatures were not measured, however, so conclusions cannot be certain. 

H nmr studies in non-polar solvents have shown that whereas the sulphide and selenide of the heterocyclic system (224) involve intramolecular coordinative interactions between tin and sulphur or selenium, the related phosphine oxide prefers to bind intermolecularly. In the solid state, a similar situation applies.Structural studies of adducts of triphenylphosphine oxide with monoorganotrichlorostannanes have also been reported. Various types of phosphine oxides are able to complex alkali and alkaline earth metal cations, and to facilitate their transfer across aqueous/organic interfaces.Organogallium complexes of phosphine oxide ligands have been isolated from the reactions of organogallium peroxo derivatives with phosphines. ... 

One simple way to increase the solubility of organic substrates in aqueous solution is the addition of co-solvents to an aqueous two-phase system. This increases the reaction rate of the Rh/TPPTS catalyst, but at the same time the selectivity drops [7]. Furthermore, it can result in troublesome phase separation and leaching of the co-solvent into the product phase [7]. Instead of the addition of co-solvents triphenylphosphine can be added to the two-phase Rh/TPPTS system. The local concentration of the active rhodimn complex at the interface will be increased, resulting in a rate enhancement in the hydroformylation of 1-octene by a factor of 10-50 [8]. The active species at the interface contains both TPPTS and triphenylphosphine hgands. Test reactions performed in methanol confirmed that this increase in reaction rate was due to promotion of interfacial catalysis. However, after recycling the catalyst Rh/TPPTS was found in the aqueous phase whereas the PPhs was in the organic phase and in the subsequent reaction with freshly added organic phase the activity of the catalyst is similar to that of the biphasic reaction in the absence ofPPhs. 

The effect of the catalyst and the hgands has not been discussed yet however, it plays an important role. For example, by replacing the classical phosphine ligands by a hydrosoluble sulfonated triphenylphosphine (TPPTS), Safi and Sinou carried out a reaction with butadiene monoxide and ethyl acetoacetate in a two-phase aqueous-organic medium.f The recycled water layer containing the catalyst could be reused with very high efficiency for a second reaction. As a matter of fact, the corresponding ethyl ester of the 2-acetyl-6-hydroxy-4-hexenoic acid was isolated in 80% and 87% yield (Z/E = 15 85) after the first and the second reaction, respectively. 

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