Phosphine oxides, phosphates

In this way, a range of polymerizable diepoxides or organophosphorus-containing curing agents based on phosphine oxide, phosphate, or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) have been prepared and evaluated (Fig. 9). 

Fig. 9 Selected phosphine oxide-, phosphate-, and DOPO-based epoxides and curing agents. (Redrawn from Ref. l)...

Tervalent phosphorus acid derivatives (1) are compounds with three covalent bonds to phosphorus and at least one electronegative atom bound directly to the phosphorus atom. Such compounds are able to undergo a diversity of reactions since they are nucleophiles due to the lone pair on phosphorus and also electrophiles because of the presence of a leaving group X. They are generally reactive towards water and often easily oxidized. They are therefore mainly used as intermediates for the preparation of more stable phosphorus compounds, such as phosphine oxides, phosphates and phosphonates. 

The phosphorus ylides of the Wittig reaction can be replaced by trimethylsilylmethyl-carbanions (Peterson reaction). These silylated carbanions add to carbonyl groups and can easily be eliminated with base to give olefins. The only by-products are volatile silanols. They are more easily removed than the phosphine oxides or phosphates of the more conventional Wittig or Homer reactions (D.J. Peterson, 1968). 

Carbodiimide formation is markedly accelerated when phosphine oxides (R PO) or phosphates are used as catalysts. Intermediates with P—NR bonds have been postulated as iatermediates ia these reactioas (59,60). 

Garbodiimide Formation. Carbodiimide formation has commercial significance in the manufacture of Hquid MDI. Heating of MDI in the presence of catalytic amounts of phosphine oxides or alkyl phosphates leads to partial conversion of isocyanate into carbodiimide (95). The carbodiimide (39) species reacts with excess isocyanate to form a 2 + 2cycloaddition product. The presence of this product in MDI leads to a melting point depression and thus a mixture which is Hquid at room temperature. 

Neutral Extractants. Many neutral organophosphoms extractants are available phosphate esters, phosphonate esters, phosphinate esters, and phosphine oxides. The most popular neutral extractant is tributylphosphate (TBP), which reacts with RE elements according to a solvation mechanism ... 

Much effort has been placed in the synthesis of compounds possessing a chiral center at the phosphoms atom, particularly three- and four-coordinate compounds such as tertiary phosphines, phosphine oxides, phosphonates, phosphinates, and phosphate esters (11). Some enantiomers are known to exhibit a variety of biological activities and are therefore of interest Oas agricultural chemicals, pharmaceuticals (qv), etc. Homochiral bisphosphines are commonly used in catalytic asymmetric syntheses providing good enantioselectivities (see also Nucleic acids). Excellent reviews of low coordinate (coordination numbers 1 and 2) phosphoms compounds are available (12). 

Under similar conditions, perfluoroalkyl iodides react with alkyl phosphates to give fluorinated phosphine oxides, phosphinates, and phosphines [54 (equation 49) The product formed depends upon the stoichiometry and type of iodide used. When sodium alkyl trithiocarbonates are used as substrates, perfluoroalkyl tri-thiocarbonates ate formed [55]. 

Phosphates, Phosphonates, Phosphine Oxides and Phosphine Sulfides 260, 544, 1433, 1513, 1564,1658... 

An unusual two-component domino Michael/aldol process was described by Tomioka and coworkers in which the initiating step is the formation of an a-lithiated vinyl-phosphine oxide [28] or vinyl phosphate [29]. 

Mixed phosphines,113 phosphates,114,115 phosphinites (diphenylphosphine oxide) and related diphenylphosphine acids,116-119 phospholes,120 and other phosphorus ligands121-123 have been used in Pt-catalyzed hydroformylation. [PtCl2(COD)] has been used as starting material for the preparation of catalytic precursors.114,124-126... 

Many of the reagents developed initially for the recovery of base or radioactive metals have also been investigated as potential PGM extractants, e.g., phosphine oxides,310-313 dialkylsulfoxides,314 dialkyl-and diphemd-thioureas,296,315-317 thiopicolinamides, thiobenzanilide,319 phosphate diesters,320 tetra-... 

Alkyl esters of phosphoric acid and phosphine oxides will extract metals and mineral acids by direct solvation. Tri-//-butyl phosphate (TBP) and tri- -octyl phosphine oxide (TOPO)... 

Tertiary amine polymethacrylates, 20 471 tertiary-butyldimethylsilyl (TBDMS), cleavage of, 16 559, 560 Tertiary creep, 13 472 Tertiary diperoxyketals, 18 457 Tertiary metal phosphates, 18 840 Tertiary nitriles, 12 180 Tertiary phosphine oxides, 19 66 Tertiary phosphines, 19 64 Tertiary recycling, 21 449 of PET, 21 450... 

Organic derivatives of phosphorus excel by the strong tendency of trivalent phosphorus to combine with oxygen or sulfur to form phosphine oxides and phosphates or their sulfur analogs. 

The same group studied the lithium cation basicities of a series of compounds of the general formula R R R PO, i.e. phosphine oxides, phosphinates, phosphonates and phosphates, by using Fourier Transform Ion Cyclotron Resonance (FTTCR) mass spectrometry. A summary of their results is shown in Figure 4. The effect of methyl substitution on LCA as well as the correlation between LCA and PA was also investigated by Taft, Yanez and coworkers on a series of methyldiazoles with an FTICR mass spectrometer. They showed that methyl substituent effects on Li binding energies are practically additive. 

From the product analyses of PET reactions of trivalent phosphorus compounds such as phosphines and phosphates, it is found that P reacts with nucleophiles such as water and alcohol to yield phosphine oxides and phosphates [92-95]. During a reaction of triphenylphosphines (P(CgH4-X-/ )3 with water to give phosphine oxides 0=P(C6H4-X-/ )3... 

Table 4.51. One-Bond (J and Longer-range (2J, 3J, 4J) Carbon-Phosphorus Coupling Constants of Representative Phosphines [372], Phosphonium Salts [365], Phosphine oxides [366, 372, 373], Phosphonium Ylides [365, 373], Phosphonates [368, 372], Phosphites [374], and Phosphates [375] (in Hz). 

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