Phenylphosphine oxide

This group has also developed two ring-contraction systems of potential use in crown synthesis. In the first of these, extrusion of a phenylphosphine oxide unit results from treatment with alkoxide ion. In the second, similar conditions initiated decarbonyla-tion of a bis-pyridyl ketone Despite the apparent potential of these methods for crown synthesis, direct formation of crowns by processes which involve them do not appear to have enjoyed great success thus far. 

Although of limited success, this Ni-catalysed coupling strategy builds on a previous report of the successful, direct synthesis of poly(4,4 -diphenylphenyl-phosphine oxide) (70c) from bis(p-chlorophenyl)-phenylphosphine oxide (71) (Scheme 21) [66]. The white soluble material (70c) (Aj ax 280 nm) was found to have a single phosphorus environment by NMR spectroscopy, a comparatively high molecular weight (Mn= 15,300) together with a low molecular... 

Finally, prochiral bis(hydroxymethyl)phenylphosphine oxide 82 was desym-metrisized using either a lipase-catalysed acetylation (Method A) or hydrolysis of the corresponding diacetyl derivative 83 (Method B), to give the chiral monoacetate 84. Application of the two reverse procedures made it possible to obtain both enantiomerically enriched forms of 84 (Equation 40). ... 

On studying a series of ammonium 1,3,2,5-dioxaborataphosphorinane oxides (111), the dependence of the tautomeric equilibrium position on amine basicity was analyzed. The equilibrium position was estimated from chemical shift values of bis(oxymethyl)phenylphosphine oxide with 8 3IP of 35 ppm being used as a model of an acyclic form and 5-Ph-5-oxo-1,3,5-dioxaphosphorinane (107, R = H) with 8 3IP of 6 ppm used as a model of a cyclic compound. The chemical shift values (111, X = 0, R = H) and dissociation constants (pKa) of conjugate acids for amines are presented in Table V. 

Preparation of bis(4-methoxyphenyl)phenylphosphine oxide — Reaction of a Grignard reagent with a phosphorus halide... 

A further illustration has appeared28 of the reactivity of simple a-keto-alkyldi-phenylphosphine oxides (31) towards addition reactions, as outlined in Scheme 5. In the same paper, alkylation of chloro(di-t-butyl)phosphine (32) by alkyl benzoates is described 28 see Chapter 3 for details. A similar acylation reaction of tetramethyl-diphosphine disulphide (33) has been described, although the acetylphosphine sulphide (34) was not isolated.29... 

The Tgs and in some cases, the Tms of several poly(arylene ether-1,3,4-oxadiazolejs are reported in Table 12. The last five polymers in Table 12 display the same Tg trend as seen for other polymers, namely phenylphosphine oxide > sulfone > carbonyl > terephthaloyl > isophthaloyl. The terephthaloyl polymer could be heated above the Tm, and subsequently quenched to the amorphous form, and then annealed at 330 °C to induce crystallinity. Once the Tms of the carbonyl and isophthaloyl polymers were exceeded, crystallinity could not be reintroduced by annealing at 300 to 330 °C for several hours. The Tg and Tm of the isophthaloyl polymer are abnormally close. 

The same procedure could be used on DiPAMPO to give (S,S)-l,2-ethane-diylbis[(o-hydroxyphenyl)phenylphosphine oxide.]. 

If a very simple reagent such as trichlorosilane (2) is applied to phenylphosphin-oxides (e. g. 9-phenyl-9-phospha-9,10-anthraquinone) the corresponding phenylphos-phine93,94 [e. g., 9-phenyl-9-phospha-anthrone (134)] is obtained (see Scheme 15). 

The first enzymatic desymmetrizations of prochiral phosphine oxides was recently reported by Kielbasinski et al.88 Thus, the prochiral bis(methoxycarbonylmethyl)-phenylphosphine oxide 93 was subjected to the PLE-mediated hydrolysis in buffer affording the chiral monoacetate (RJ-94 in 72% ee and 92% chemical yield. In turn, the prochiral bis(hydroxymethyl)phenylphosphine oxide 95 was desymmetrized using either lipase-catalyzed acetylation of 95 with vinyl acetate as acyl donor in organic solvent or hydrolysis of 97 in phosphate buffer and solvent affording the chiral monoacetate 96 with up to 79% ee and 76% chemical yield. 

Under the reaction conditions it spontaneously fragments to give the product alkene and tri-phenylphosphine oxide. 

Kielbasinski, P., Rachwalski, M., Kwiatkowska, M., et al. 2007b. Enzyme-promoted desym-metrization of prochiral bis(cyanomethyl)phenylphosphine oxide. Tetrahedron Asymmetry, 18 2108-12. 

In 1962, Mannerskantz and Wilkinson described the reactions of [Mo(CO)4(2,5-dithiahexane)l with X2 (X = Br, I) to give the seven-coordinate complexes [MoX2(CO)3(2,5-dithiahexane)]. Treatment of the oxygen donor ligand complexes [M(CO)3(RPPh)] (M = Mo, W) RPPh = bis[(di-phenylphosphinyl)methyl]phenylphosphine oxide, [M2(CO)6(MDPO)] MDPO = methylenebis[diphenylphosphine oxide], and [M(CO)4(R... 

Finally, the carboxylate anion acts as a nucleophile to displace tri-phenylphosphine oxide and give the inverted product. 

A variety of bis(2-hydroxyaryI)phenylphosphine oxides (15) have been prepared from diaryl phenylphosphonates (14) by based-induced double 1,3-migration of phosphorus from oxygen to carbon. ... 

Treatment of (5 ,5)-bis(2-hydroxypropyl)phenylphosphine oxide with initially base followed by Cl(CH2)20(CH2)20Tf gave the dichloride intermediate, which with base and either catechol or tosyl amine in DMF and elevated (150 °C) temperatures generated the macrocyclic phosphane oxide 35 in 15% yield or the l-phospha-10-aza-18-crown-6-ether in 44% yield <06EJOC154>. 

Trlphenylphosphine ylides are cleaved by sodium periodate to tri-phenylphosphine oxides and carbonyl compounds (equation 542) [1195]. 

Pietrusiewicz and coworkers have developed methods for the synthesis of homochiral phosphine oxides. They play an important role in asymmetric synthesis as chiral ligands for catalysts. The readily prepared (5/ )-ethyl[(menthoxycarbonyl)methyl]phenylphosphine oxide (13) can be deprotonated, alkylated and then decarboxylated to afford the homochiral (/7j,)-alkylethylphenylphosphine oxides (Scheme 12). Pietrusiewicz and Zablocka have also described the synthesis of chirally pure a, 3-unsaturated phosphine oxides. ... 

Complex 6 also exhibits catalytic activity in the oxidation reaction of various other substrates such as PPh3, dibenzylamine, and CO, with formation of tri-phenylphosphine oxide, /V-benzylidenebemzylamine, and C02, respectively. 

Triphenylphosphirene oxide (2).4 This potentially aromatic heterocycle has been obtained by treatment of bis-(a-bromobenzyl)phenylphosphine oxide (l)5 in benzene solution with DBN. Stille et al. suggest that the conversion of (1) to (2) proceeds by a... 

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