Phosphine triaryl

Phosphine, methyl-n-propylphenyl-rhodium complexes asymmetric hydrogenation, 6,250 Phosphine, neomenthyldiphenyl-rhodium complexes asymmetric hydrogenation, 6,250 Phosphine, phenyl-, 2,992 Phosphine, o-phenylenebis(dimethyl-, 2,993 Phosphine, p-phenylenebis(diphenyl-, 2,993 Phosphine, seleno-metal complexes, 2,664 bidentatc, 2, 664 Phosphine, triaryl-photographic stabilizer, 6,103 Phosphine, tributyl-, 2, 992 oxide... 

Related Reagents. (5)-2-(2,6-dimethoxyphenyl)oxazole hexamethylphosphoric triamide (5)-BINAP (+ )-DIOP trialkyl phosphines triaryl phosphines etc. 

Trialkyl- and triaryl-phosphines react with 1,3-benzodithiolylium ions to give a phos-phonium salt which is deprotonated by n-butyllithium to give (221) (76TL3695). 

Besides the thiocyanates, just mentioned, other 5-donor complexes which are of interest are the dialkyl sulfides, [MCl3(SR2)3], produced by the action of SR2 on ethanolic RhCl3 or on [IrClg] ". Phosphorus and arsenic compounds are obtained in similar fashion, and the best known are the yellow to orange complexes, [ML3X3], (M = Rh, Ir X = Cl, Br, I L = trialkyl or triaryl phosphine or arsine). These compounds may exist as either mer or fac isomers, and these are normally distinguished by their proton nmr spectra (a distinction previously made by the measurement of dipole moments). An especially... 

Complex amine formation from cyclic anhydride and aromatic amine formation of triaryl phosphine Sterling Organics Amery et al. (1994)... 

The first examples of five-coordinate platinum(II) complexes of the type [Pt(PR3)L]2+ (L = tris(2-(diphenylphosphino)ethyl)phosphine R = Et, OMe, OEt) (104) containing only P-donor atoms have been prepared by the reaction of [PtClL]+ with an appropriate monodentate tertiary phosphine or phosphite ligand.284 Triaryl phosphines and phosphites do not react with the precursor complex, even at elevated temperatures, most probably due to the considerable steric interactions that would occur upon the approach of the P-donor ligand to the platinum(II) center. 

This is an extremely useful reaction for the synthesis of alkenes. It involves the addition of a phosphonium ylid, e.g. (136), also known as a phosphorane, to the carbonyl group of an aldehyde or ketone the ylid is indeed a carbanion having an adjacent hetero atom. Such species are generated by the reaction of an alkyl halide, RR CHX (137), on a trialkyl- or triaryl-phosphine (138)—very often Ph3P—to yield a phosphonium salt (139), followed by abstraction of a proton from it by a very strong base, e.g. PhLi ... 

The need for higher product specificity and milder reaction conditions (see also Section IX) has led to extensive research in hydroformylation technology. This research, as reported in technical journals, patent literature, and commercial practice has been primarily concerned with catalysis by rhodium, in addition to the traditional cobalt, and with catalyst modification by trialkyl or triaryl phosphines. These catalyst systems form the basis for the major portion of the discussion in this chapter some other catalyst systems are discussed in Section VIII. 

The organometallic side-product MAr is conveniently removed by selective reaction with a proton source such as Bu Cl or NH4C1. This reaction is extremely effective for certain symmetrical triarylphos-phines and for mixed aralkylphosphines. However, detailed investigations of P-C cleavage in functionalized and/or unsymmetrical triaryl-phosphines (17-19) indicate that such reactions are far from straightforward. The products obtained on treatment of triarylphos-phines of type IV or V with alkali metals depend both on the nature of the substituents X and on the alkali metal. 

Values of ka and b are correlated by the Hammett equation for pyridines and for triaryl phosphines. Very large negative p values were found for pyridine reactions especially (35). Key values are highlighted in Table II. 

The reactions of trialkyl and triaryl phosphines (R3P) with a wide variety of bare transition metal ions have not yet been studied but it is possible to get a phosphine such as Ph3P into the gas phase (145). Figure 6 shows the reaction of Eu+ with Ph3P. The addition of only two phosphine molecules was observed under the conditions used (113) (Ph3P at an uncorrected pressure of 2 x 10-6 Pa). The spectrum also shows the addition of only one Ph3P to [EuO]+. 

Shell Chemical has a process that does both the Oxo reaction and hydroformyiation in one step in the same reactor. They use a special catalyst, thought to be cobalt modified with a trialkyl or triaryl phosphine ligand— but they are holding this one pretty close to the vest. Overall yields are 70-80%, with straight-chain alcohols representing greater than 80%. Major by-products are paraffins that are recovered and used to make olefins and then recycled back as feed. This process can also use internal olefins (with the double-bond somewhere besides the alpha position) and yield similar normakiso alcohol ratios. ... 

---