Methylphosphinate, reaction with

With ethyl iodide, ethylphosphine and phosphine are formed. The reaction with excess silyl bromide results in the formation of silylphosphine. Silylphosphine, like methylphosphine, forms an adduct with diborane... 

Both methylphosphine (this synthesis) and dimethylphosphine (the following synthesis) are considerably stronger Lewis bases than phosphine, and their reactions with various Lewis acids, including boranes, have been the subject of recent studies. Both methylphosphine and dimethylphosphine are readily oxidized by air, and thus can serve as sources of methylphos-phonous (methylphosphinic) acid, CH3PHO(OH), and dimethyl-phosphinic acid, (CH3)2PO(OH). ... 

Metalations of various methylphosphines by BuLi-TMEDA were studied by Peterson (27) and by Rausch and Ciappenelli (II). Whereas methyldiphenylphosphine, for example, is inert to BuLi in hydrocarbon solvents, addition of an equivalent of TMEDA gives (diphenylphosphino)-methyllithium in 40-75% yield. Dimethylphenylphosphine and dimethyl-n-octadecylphosphine can also be converted into a-phosphinoalkyllithium compounds in similar yields with BuLi-TMEDA. The utility of these reagents as intermediates in synthesizing carbon functionally substituted phosphines was demonstrated by reactions with diphenylchlorophosphine, benzophenone, carbon dioxide, etc. 

There are several reports about the nucleophilic addition of 0-methyl methylphosphinate with aldehydes. The synthetic methods of 0-methyl (1-hydroxyalkyl)methylphosphinates M12 with different reaction conditions are summarized as three kinds of methods ... 

O-Methyl [1-(substituted phenoxyacetoxy)aIkyl]methylphosphinates IIIA-IIIG including 54 compounds were easily synthesized by condensation of O-methyl (1-hydroxyatkyl)methylphosphinates M12 with substituted phenoxyacetyl chlorides MS in the presence of base under mild reaction conditions. 

Organophosphorus compounds. Phosphorus-carbon bond fonnation takes place by the reaction of various phosphorus compounds containing a P—H bond with halides or tritlates. Alkylaryl- or alkenylalkylphosphinates are prepared from alkylphosphinate[638]. The optically active isopropyl alkenyl-methylphosphinate 778 is prepared from isopropyl methylphosphinate with retention[639]. The monoaryl and symmetrical and asymmetric diarylphosphi-nates 780, 781, and 782 are prepared by the reaction of the unstable methyl phosphinate 779 with different amounts of aryl iodides. Tnmethyl orthoformate is added to stabilize the methyl phosphinate[640]. 

More than 35 years ago, it was reported that the reaction of tri-methylphosphine with the cyclotetraphosphine (CF3P)4 affords the phosphine-phosphinidene complex, Me3P —> PCF3 (43). More recently, it has been demonstrated that stable carbenes are sufficiently nucleophilic to effect the depolymerization of cyclopolyphosphines and cyclopolyarsines to produce carbene-pnictinidene complexes 66-70, the first examples of p-block pnictinidenes (44, 45). Two extreme canonical forms, 71 and 72, can be written for such species. Structure 71... 

The reaction of O-ethyl methylphosphinate (1567) and diethyl aceta-midomethylenemalonate (1568) in the presence of sodium ethoxide gave an addition product (1569), which was then hydrolyzed with concentrated hydrochloric acid [74RC1119 83PS( 17)21],... 

Benzoyl chloride (2.61 mL, 22.5 mmol) was added to a stirred, cooled (0°C) solution of (R)-ferf-butyl(hydroxylmethyl)methylphosphine-borane (92% ee, 2.22 g, 15.0 mmol) in pyridine (10 mL) and the mixture was warmed to room temperature. After 1 h, the reaction mixture was quenched with 2 M aqueous HCl. 

To a stirred solution of benzoyloxy(tcrt-butyl)methylphosphine-borane (99% ee, 6.06 g, 24 mmol) in acetone (25 mL) was added a solution of potassium hydroxide (4.0 g, 72 mmol) in water (15 mL) dropwise. After completion of the hydrolysis (ca. 1 h), the reaction mixture was diluted with water (lOOmL) and extracted three times with diethyl ether. The combined extracts were washed with brine and dried over Na2S04. The solvent was evaporated and the resulting crude (/f)-tert-butyl(hydroxymethyl)methylphosphine-borane was dissolved in acetone (70 mL). The solution was added to a vigorously stirred, cooled (0°C)... 

As a typical example from industrial practice we consider the simulation of a process with the reaction of methylphosphinic acid and butanol to methylphosphinic acid butyl ester and water, which was modeled by Gordana Hofmann-Jovic at InfraServ Knapsack [C28]. Because of the lack of experimental data for the binary systems with phosphorous compounds, COSMO-RS was used for the prediction of the binary activity coefficients. Then the results were fitted by an NRTL equation and the entire process was modeled by a commercial process simulator. The resulting phase diagrams were in close agreement with experimental measurements obtained later (Fig. 8.2). 

We have studied the reaction of methyl trifluoromethanesul-fonate (methyl triflate) with isopropyl methylphosphinate (1), and have used this system to develop a new procedure for the stereospecific synthesis of trivalent (P ) organophosphorus esters. 

In the meantime, Knowles and his colleagues had prepared and tested different chiral phosphines with stereogenic phosphorus atoms. It was thought that asymmetry needed to be as near as possible to the metal because the catalytic reaction takes place in the coordination sphere of the metal the substituents on the phosphorus were varied and the best results were obtained when phosphines such as the o-anisyl(methyl)phenylphosphine (PAMP) and o-anisyl(cyclohexyl)methylphosphine (CAMP) were used (Figure 12). 

Hexadiene reacts stereoselectively with both chlorodimethylphosphine and dichloro-methylphosphine to give 2,5-dihydrophospholes in which the methyl groups at C-2 and C-5 in the phosphole ring are cis orientated. This result can be explained mechanistically by a concerted disrotatory process, analogous to the reaction of sulfur dioxide with 1,3-dienes15,... 

Treatment of trichlorogermylphosphine 183 with a twofold excess of DBU in tetrahydrofuran gave bis[bis(trimethylsilyl)methyl]diphosphene (186), bis(trimethylsilyl)methylphosphine (187), and diphosphine 188 in the proportions 55 25 20. The proposed reaction mechanism is depicted in Scheme 4. Compound 184 was probably first formed through the elimination of germanium dichloride, and then reacted further with an excess of DBU in two competitive reaction routes to give compounds 186-188. Intermolecular dehydrochlorination of 184 afforded diphosphene 186, while intramolecular dehydrochlorination of 184 resulted in 187 and 188 via the triplet phos-phinidene intermediate 185 (84CC1621). 

P. Thenard may have prepared methylphosphines in 1845 by the reaction of chloro-methanes with calcium phosphide (258, 259). His father, L. J. Thenard, did some early research on Cadet s liquid (257). 

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