Ethyl diphenylphosphinite

The kinetics of formation of phosphonates by reaction of o-dinitrobenzene with phosphites have been examined. The energy of activation for the reaction increases as the nucleophilicity of the phosphite decreases, e.g. ethyl diphenylphosphinite 14kcalmol"S diethyl phenylphosphonite 16 kcalmol S and triethyl phosphite 21kcalmol . An intermediate of the type (61), formed by nucleophilic attack of the phosphite, was proposed. In (61) there is a particularly favourable electrostatic interaction. That p-dinitrobenzene is unreactive, is thought to stem from the fact that this compound cannot form an intermediate with such a stabilizing factor. 

The Schlenk flask was charged with [Ir(COD)Cl]2 (83 mg) and 2mL of dry dichloromethane. (45,55)-(9- [ 1 -Benzyl-1 -(5-methyl-2-phenyl-4,5-dihydro-oxazol-4-yl)-2-phenyl-ethyl]-diphenylphosphinite (125 mg) was dissolved in anhydrous dichloromethane (5mL) under an argon atmosphere, and added to the metal precursor. The so-formed orange/yellow solution was heated at reflux for 1 h. 

Ethyl diphenylphosphinite, (C6H5)2POC2H5 (1). Supplier Aldrich. 

Peptides. A new amide or peptide synthesis is based on the formation of iminophosphoranes, R N=PR3, from the reaction of azides with a tertiary phosphine. These phosphoranes react with carboxylic acids to form amides.1 Ethyl diphenylphosphinite is more useful than a triarylphosphine because the by-product is hydrolyzed to diphenylphosphinic acid, which can be readily removed. The iminophosphorane 2, derived from 1 and ethyl azidoacetate, reacts with CboGly-L-Phe-OH to give optically pure 3 in 70% yield.2... 

Ethyl diphenylphosphinite, 131 Thionyl chloride, 297 to anhydrides Tetracyanoethylene, 289 of esters to amides... 

Ethyl diphenylphosphinite, 131 Hexamethyldisilazane, 141 Thionyl chloride, 297 Zirconium(IV) acetylacetonate, 351 From other starting materials Acetohydroxamic acid, 2 Bis(benzonitrile)dichloropalladium(II), 34... 

Benzotriazolyl diethyl phosphate, 28 N,N-Bis(2-oxo-3-oxazolidinyl)phos-phoramidic chloride, 39 Ethyl diphenylphosphinite, 131 Thionyl chloride, 297 N-Protected amino acids /-Butyldimethyl silyl trifluoromethane-sulfonate, 50... 

Ramirez et al. reported the reaction of 1,2-dibenzoylethylene with ethyl diphenylphosphinite to give the crystalline phosphorane (370). />-Bromobenzaldehyde adds to (370) forming the stable bicyclic dioxyphosphorane (271) (Scheme 77). The structure of the product was confirmed by x-ray crystallography the phosphorus atom formed a trigonal bipyramid with the two oxygens apical and the carbon atoms equatorial <64JA5339,7UA5236>. 

Similarly, ethyl diphenylphosphinite was obtained from reaction of the phenyl Grignard reagent with the ethyl ester. 

Ethyl diphenylphosphinite, (CgHg)2P.OC2H5, is formed when diphenylchlorophosphine m ether solution is treated with sodium ethoxide. The product is a transparent hquid, B.pt. 179° C. at 14 mm., density 1-0896 at 0° C. It forms an additive compound with copper iodide, M.pt. 190° to 191° C. Under the catal3rtic influence of ethyl iodide at ordinary temperature it is transformed into ethyldiplienyl-phospliine oxide. During the preparation of the phosphinite some ethyl diphenylphosphinate, (CgH5)2PO(OC2H5), is obtained as a byproduct. 

Ethyldiphenylphosphine oxide, (C2Hg)(C6H5)2TO, occurs when the phosphonium compound is treated with silver oxide as before, or can be obtained from ethyl diphenylphosphinite, (CgH5)2P.OC2H5, under the catalytic influence of ethyl iodide at room temperature. It separates from boihng ether in colourless, glistening prisms, M.pt. 121° C. 

The Michael-Arbuzov rearrangement is a basic reaction for the preparation of 4-coordinate species including phosphine oxides from 3-coordinate phosphorus esters, such as phosphinous esters. In most cases, the reaction requires a prolonged heating above 100 °C. Odinets et al. have now succeeded in carr5nng out the Arbuzov-reaction of ethyl diphenylphosphinite with a variety of alkyl halides in ionic liquids at or below 110 °C in short reaction times, mostly within half an hour. The best ionic liquid was l-hexyl-3-methylimidazolium bromide (Scheme 2). The recovered [hmim]Br could be recycled at least five times without a decrease in activity. 

The reaction of 1,1-dibromo-l-alkenes with ethyl diphenylphosphinite in the presence of CS2CO3 in boiling toluene furnished aHqmylphosphine oxides (Scheme 6). The first step is the elimination of HBr that is followed by the addition of the P-reagent. The final step is the Michaelis-Arbuzov type fission of the phosphonium salt intermediate. ... 

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