Arylations phosphine, tris

Numerous alkyl and aryl phosphine, arsine and stibine compounds are described as being silver solvents. Examples are tris(p-hydroxyphenyl)phosphine and bis(2-carboxyethyl)methyl-phosphine.72... 

Tricyclic phosphinous chloride 79 reacted with tri-isopropylphenyl magnesium bromide and gave P-arylated phosphine 80 <2002HAC626> (Equation 6). 

The authors found that branched alkyl phosphines were not useful at all, whereas aryl phosphines afforded 1145 in acceptable yield but modest trans/cis selectivity (Scheme 1.298). However, both triethylphosphine and tri- -butylphosphine produced 1145 in nearly quantitative yield with 100 0 trans/cis selectivity. Operationally, the phosphonium salts were generated in situ, triethylphosphine was the reagent of choice. Similarly, the tranr-2-alkenyl bis- and ttis-oxazoles 1147—1150 were readily prepared. A further application of this methodology for the synthesis of ulapuahde A is discussed in Section 1.5.6. 

The air-stabilities of the complexes in Table I vary widely. Isocyanide complexes and complexes of the alkyl phosphines are very air sensitive or pyrophoric. The aryl phosphine complexes are moderately air sensitive the phosphite complexes can be handled in air but should be stored in an inert atmosphere. The phosphite complexes are insoluble in polar solvents such as alcohols and water, and soluble in hydrocarbons. Aryl phosphine complexes are soluble in aromatic solvents or tetrahydrofuran and insoluble in alkanes and alcohols. The alkyl phosphine complexes are soluble in ethers and hydrocarbons the triethylphosphine complex dissociates to the deep-purple tris complex, and is protonated by alcohols. 

The mixed triarylphosphine 787 can be prepared by the reaction of (trimethylsily )dipheny phosphine (786) with aryl halides[647]. Ph3P is converted into the alkenylphosphonium salt 788 by the reaction of alkenyl tri-flates[648]. 

Restricted rotation has been observed in tris-o-tolylphosphine sulphide and selenide (39). The spectrum of the selenide shows two methyl environments in the ratio 2 1 at 30 °C but the methyl signals of the sulphide resolved to this pattern only upon cooling the sample. The corresponding oxide and the parent phosphine showed only one methyl environment down to — 60 °C. Y-Ray diffraction of the selenide showed that the methyl group on one aryl group is directly behind the phosphorus atom in the crystal, as shown in (39). 

Diphosphenes stabilised by bulky groups, e.g. (157, R = 2,4,6-tri-t-butylphenyl), can be isolated in high yield from the reactions of alkyl- or aryl-(trichlorogermyl)phosphines with an excess of the base DBU. The formation of less sterically crowded systems, e.g. (157, R = t-butyl), is also possible by this route,... 

In 1998, Miyaura reported a Rh(acac)(CO)2/dppp-catalyzed addition of aryl or alkenylboronic acids to aldehydes in aqueous organic mixtures under an inert atmosphere (Eq. 8.85).216 The use of electron-rich tri(tm-butyl)phosphine as ligand was found to be beneficial for obtaining good yields of the corresponding aldehyde addition products.217... 

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