Diethyl vinylphosphonate, preparation

The halohydroxylation method has been developed for exploiting the reactivity of the double bond present in dialkyl vinyl- and propenylphosphonates. Preparation of the halohydrins of diethyl vinylphosphonate failed using NBS or NBA. Treatment of diethyl vinylphosphonate on large scale with NaOCl or NaOBr in aqueous medium at pH < 3 gives the halohydrins with the hydroxyl group in the P-position (anti-Markovnikoff addition) with 95% or 65-85% purity, respectively (Scheme 4.9). As a consequence of the acid conditions, the preparation of halohydrins is generally accompanied by the formation of undesired diethyl 1,2-dihalogenophosphonates. ... 

Diethyl 2-(cyclohexylamino)vinylphosphonate has proved to be an excellent reagent for conversion of aldehydes and ketones into the corresponding a,/J-unsaturated aldehydes.4,B Preparation of formylmethylenetriphenylphosphorane8 and diethyl 2,2-(diothoxy)ethylphosphonate7 have been reported and used for the conversion of aldehydes, but not ketones and hindered... 

The report of an efficient one-pot procedure for the preparation of 3-indolylphosphonate in 88% yield using diethyl 2-dimethylamino-l-(2-nitrophenyl)vinylphosphonate is of special interest (Scheme 5.77). After reduction, the presence of a nitro group in the ortho position provokes a spontaneous transamination reaction. This provides a straightforward approach to 3-indolylphos-phonate derivatives from easily available benzylphosphonates. ... 

Another procedure for the preparation of dialkyl 2-oxoalkylphosphonates features the trapping of acyl chlorides by phosphonate carbanions produced by the conjugate addition of organolithiums or organocuprates to vinylphosphonates, as illustrated by the conversion of diethyl l-(trimethylsi-lyljvinylphosphonate into diethyl l-ethyl-2-oxobutylphosphonate in 80% yield (Scheme 7.25) ... 

Oxygen and nitrogen nucleophiles add to diethyl l-(ethoxycarbonyl)vinylphosphonate to generate the formation of various fused heterocyclic compounds. Thus, A -carbapcncrns are readily prepared by the Michael addition of A-lithio-4-vinylazetidin-2-one to diethyl l-(ethoxycarbo-nyl)vinylphosphonate followed by ozonolysis of the adduct and subsequent treatment of the generated aldehyde by intramolecular Homer Wadsworth-Emmons reaction (Scheme 8.28). ... 

Reagent grade pentane passed through Merck anhydrous neutral alumina was used. Crystallization was carried out at 0° using 50 ml. of dry pentane. Filtration of the crystals was carried out under dry nitrogen. The submitters succeeded in crystallizing diethyl 2-(cyclohexylamino)vinylphosphonate only after the publication of its preparation. The crystalline product is stable for several months, if stored at 0° under anhydrous conditions. 

Treatment of 1 with two equivalents of nBuLi in a mixture of hexane -THF at -65 °C followed by the addition of the carbonyl compounds gave after hydrolysis the corresponding ot-chloro-a,P-unsaturated acids [242c]. Diethyl 1-chloroalkylphosphonates are used for the preparation of diethyl 1,2-epoxyalkylphosphonates [243-246], and 1-(methylthio)methylphosphonate [247], as well as derivatives of alkyidenediphosphonates and vinylphosphonates [248],... 

MIP catalysts. Efendiev etal. have performed seminal research in which the oxidation of ethylbenzene to acetophenone was studied (Scheme I4).36a,37 Having copolymerized the diethyl ester of vinylphosphonic acid with acrylic acid, the resulting polymer was then functionalized with Co(II) complexes, while the template was added. A series of polymers were prepared in which the template was the substrate, an analog of the intermediate, or the product itself. Cross-linking of the prearranged polymer was effected using /V,/V-methylenebis(acrylamide), and a control polymer was prepared which did not contain imprinted sites. The substrate-imprinted polymer displayed a catalytic... 

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