Water-trialkylphosphine oxide

B. By Hydrolysis Reactions.—Details have appeared of the synthesis of dibenzophosphorin oxides (15) from 5-alkyldibenzophospholes, by reaction with methyl propiolate in the presence of water, and of confirmatory syntheses from phosphinic acid chlorides, as shown below. Evidence for the suggested mechanism of the ring-expansion reaction is presented. The hydrolysis of enamine phosphine oxides is an efficient, although somewhat indirect, method for the preparation of j8-ketoalkylphosphine oxides (16) [see Section 3(iii), for the preparation of enamine oxides]. Reasonable yields (48—66%) of trialkylphosphine oxides (17) have been obtained by the alkaline hydrolysis of the products from the pyrolysis at 220 °C of red phosphorus with alkyl halides, in the presence of iodine. 

For example, direct treatment of red phosphorus with potassium hydroxide in a mixture of dioxane and water with a phase-transfer catalyst (benzyltriethylammonium chloride) allows direct reaction with primary haloalkanes to form the trialkylphosphine oxide in moderate (60-65%) yield.1415 Allylic and benzylic halides are similarly reported to generate the corresponding tertiary phosphine oxides. When the reaction is performed with a,(o-dihalides, cyclic products are generated only with four- and five-carbon chains the third site... 

Neutral-Species Extractants. Ketones, ethers, linear poly-ethers, and more recently, macrocyclic or "crown ethers all have useful properties as extractants if they are sufficiently water insoluble. Sulfoxides, the trialkyl phosphates, the trialkylphosphine oxides, and the carbamoylmethylphosphonates are among the stronger coordinators classified as neutral species extractants. These compounds usually coordinate directly with the metal ion and supply coordination that would be suppli by water in the aqueous phase. 

With strongly basic trialkylphosphines water may be oxidatively added to give cationic hydrido complexes, as in the case of the water-soluble ligand P(CH2CH2OH)3 3... 

The oxidative addition of water is observed with electron-rich trialkylphosphine complexes of Ir1 and Pt°, as well as with dialkyl complexes of Pdn and Ptn.35 In the latter case, the initially formed M(H)(OH) complex is immediately hydrolyzed, to give products such as (21-IX(a)).36 Note that for M = Pd these provide rare examples of thermally stable Pd,v species. 

METHYL IODIDE (74-88-4) Heat, light, and moisture contribute to instability. Reacts slowly with water, steam, or moisture in air, forming corrosive hydrogen iodide. Violent reaction with oxygen (above 570°F/298°C), silver chlorite, trialkylphosphines. Incompatible with strong oxidizers, alkali metals and alkaline earth metals, sodium. Forms explosive heat-, friction-, shock-sensitive compound with silver chlorite. 

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