Diarylphosphinic acids

It is difficult to conceive of these o-jt type transfers in compounds such as (Ci2Fg)2Si, as shown in Scheme 6. These fused-ring compounds are analogous to the intermediates proposed for the boron compounds (Scheme 5) and for the mass spectra of diarylphosphinic acids in which... 

Fine-Tuning the Redox Potential of Mn404L6 Cubes by Use of Substituted Diarylphosphinic Acids... 

Alkylbenzenes react analogously isomer proportions in the products are reported by Baldwin and his co-workers.153 The yield of aryldichlorophosphine decreases rapidly with increasing alkyl substitution of the ring it is already zero with mesitylene. As a variation of the process, the diarylphosphine oxides, together with small amounts of the diarylphosphinic acids, can be obtained by hydrolysis of the insoluble POCl3/AlCl3 complex. 

Ethylbenzene gives no diarylphosphine oxide, but instead 52 % of dichlorophosphine and 36 % of diarylphosphinic acid. 

In spite of the moderate yields (generally 20-50%), the process is of great interest because, unlike the reaction of PC13/A1C13 with aromatic compounds (page 711), it gives products that are free from isomers. Small amounts of diarylphosphinic acids are formed as by-products. 

The formation of small amounts of symmetrical diarylphosphinic acids in the reactions between aryldiazonium salts and PCI3 is complemented by the use of phosphonous dichlorides, the products being the non-symmetrical diarylphosphinic acids, ArAr P(0)OH . ... 

At this juncture, it may be noted that aryltetrachlorophosphoranes have been used to provide a wide range of derivatives of arylphosphonic and diarylphosphinic acids, as... 

Dibenzophosphole oxides are prepared by the direct oxidation (H2O2) of the phospholes <69JOCl777> a diarylphosphinic acid can also be used for generating the phosphole ring <56JOC238, 59JOC638) (Equation (28)). 

A general and efficient method for the microwave-assisted synthesis of mono- and diarylphosphinic acids (579) and (581) from anihnium 7f-phosphinate (580) and aryl halides, using Pd(0) and Xantphos as a supporting ligand, has been developed by Stawihski and Kalek (Scheme A2)P The procedure was highly efficient and provided a rapid access to a broad spectrum of arylphosphinate derivatives. 

The simple dialkyl and diarylphosphines are liquids with unpleasant odors and are susceptible to oxidation. The products of most secondary phosphine oxides tend invariably to be the phosphinic acid produced by tautomerization and further oxidation. 

In continuous operation consecutive phosphorus-containing products are formed which also influence the activity of the rhodium center and thus contribute to the catalyst deactivation. One of the main degradation products from TPPTS is the sodium salt of m-formylbenzenesulfonic acid, which indicates the insertion of the rhodium atom into the P—C bond. The arylrhodium species in which rhodium has replaced one phosphorus atom presumably exists as a phosphido-bridged dimer which is inactive. This compound may subsequently be converted to a series of consecutive products, e.g., alkyl-diarylphosphines, which act as catalyst poisons. 

Cyanadons. Aluminum complexes of BINOLs (1) that are armed at C-3 and C-3 with diarylphosphine oxide groups possess both Lewis acid and base centers. Asymmetric cyanation of aldehydes and mines with MeaSiCN, and of quinolines and isoquinolines in a manner analogous to the Reissert reaction is successful (ee 70-90%). The asymmetric Strecker synthesis is applicable to conjugated aldimines and the higher reactivity of Me SiCN than HCN in the presence of 10 mol% of PhOH enables its use in catalytic amount while supplying stoichiometric HCN as the cyanide source. 

The kinetics of the oxidation of diarylphosphine oxides with perbenzoic acid have been investigated and the kinetic deuterium isotope effects... 

Diarylphosphinic halides condense at room temperature with Grignard reagents to give unsymmetrical phosphine oxides (150). A control reaction with diphenylphosphinic acid and the ethyl Grignard reagent clearly showed that the acid was not an intermediate, as it was re-... 

The interaction of a phosphinothioic acid (or a dialkyl phosphorothioic acid) with an alkyl isocyanide yields the corresponding A-alkylthioformamide together with a monothio anhydride (reaction 21) ". A further interesting sequence commences with the interaction of a diarylphosphine oxide, R2P(0)H (R = Ph or p-Tol) with HCNS. It is known that such... 

Diarylphosphinic and diarylphosphoric azides are rapidly hydrolysed by water to diarylphosphinic and diarylphosphoric acids, respectively. Monophosphazenes are obtained by reaction with phosphines (7.225). Methyl phosphonic diazide (7.223c) can be obtained by reacting methylphosphonic dichloride with sodium azide in pyridine (7.226), while phosphoryl triazide is obtainable with... 

Synthesis and characterization of a new type of crown ethers (81)-(83) have been deseribed by Huszthy. The electronic circular dichroism (BCD) spectra of the ehiral crown ethers (i ,i )-(81) and (i ,i )-(82) eontaining an alkyl diarylphosphinate moiety, showed a strong exciton splitting in the Bb spectral region of the aromatic chromophores. In the case of the proton-ionizable ehiral derivative (i ,i )-(83) containing the phosphinic acid unit, the BCD speetrum measured in MeCN, suggested molecular dimerization or aggregation. 

Scheme 5-156). This reaction proceeds with nueleophilic phosphor compounds such as diarylphosphines, anilinium phosphinate, anilinium hypophosphite, hypo-phite esters or hypophosphorous acid. ... 

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