Phosphonoacetates synthesis

Corbel, B., L Hoslis-Kcrvclla, I., and Haelters, J.-P, Acylation of diethyl phosphonoacetic acid via the MgClj/EtjN system. A practical synthesis of P-keto phosphonates. Synth. Commun., 30, 609. 2000. Kim, D.Y., and Suh, K.H., Solid phase acylation of phosphonoacetates. Synthesis of P-keto phosphonates from polymer bound phosphonoacetate, Synth. Commun.. 29. 1271, 1999. 

Kim, D.Y., and Suh, K.H., Solid phase acylation of phosphonoacetates. Synthesis of P-keto phosphonates from polymer bound phosphonoacetate, Synth. Commun., 29, 1271, 1999. 

Another multicomponent synthesis giving N-3-substituted compounds 28 consisted of the sequential reaction of metallated phosphonoacetates, in one pot, with a nitrile then an aldehyde and finally an isocyanate. This was an extensive study of the scope and limitations of the different substituents on all the components. The most important feature was that, for good yields, the isocyanate should bear an electron-withdrawing group - tosyl was the most successful. However, an exchange reaction could be carried out by reaction of the tosyl products with aryl isocyanates under microwave irradiation, giving the N-3-aryl derivatives 29 <06CEJ7178>. 

In 1969, Szantay and co-workers published a linear synthesis of (+)-yohimbine and (—)-P-yohimbine (75) in full detail (220). Tetracyclic key intermediate 400, obtained from 3,4-dihydro-p-carboline and a properly substituted a,p-unsatu-rated ketone (173), was treated with a proper phosphonoacetic acid derivative to give unsaturated nitrile 401 or unsaturated ester 402. Catalytic reduction of the latter resulted almost exclusively in 404 with normal stereo arrangement, while reduction of 401 supplied a mixture of normal and epialloindolo[2,3-a] quinolizines 403 and 405, respectively. Dieckmann ring closure of diester 404 gave 18a-methoxycarbonylyohimbone (407) as the thermodynamically favored... 

General.—The relatively unreactive diethyl arylmethylphosphonates have been used quite successfully in alkene synthesis with phase-transfer catalysis.100 In a comparative study it was shown that anions derived from /S-ketophosphonamides (109) have very low reactivity whereas those from 0-ketophosphonates (110) react quite well with aldehydes to give frwjj-alkenes.101 Benzyl dimethyl phosphonoacetate (111) can be used to form alkenes, e.g. (112), from which the benzyl group can be removed by hydrogenolysis without disturbing the C=C bond.102 The carbanions (113) can be... 

Having established a very effective method for the synthesis of tricar-bonyl(T74-vinylketene)iron(0) complexes, Thomas has subsequently undertaken the most comprehensive study on the reactivity of these complexes to date. The reactions of 221 with phosphoramidate anions,90134 coordinating ligands such as phosphines3 and isonitriles,69,87,89,135,142,143 a variety of nucleophiles,86,89135142 phosphonoacetate anions,88,89 alkynes,108,109,144,145 and al-kenes146,147 have ah been investigated. Crucially, Thomas has also developed a method138 for the kinetic resolution of the vinylketene complexes (221) that ultimately yields enantiomerically pure samples of the complex. This... 

The Reformatsky type of reaction with Zn(0) was performed in situ and led to somewhat unstable phosphonodiamidite (step a) which was coupled with 5 -DMTr-thymidine to give the intermediate mononucleoside phospho-noamidite (step b). The latter was further coupled with 3 -acetyl-thymidine (step c). Couplings described in steps b and c were activated by tetrazole. The intermediate dinucleoside phosphonite was oxidized with (lS)-(+)-(10-camphorsulphonyl)oxaziridine (step d) or sulfurized with Beaucage reagent. The phosphonoamidites mentioned above were used in the solid-phase chemical synthesis of phosphonoacetate and thiophosphonoacetate oligonucleotides. 

The Wittig-Horner (W-H) reaction is a versatile method for the synthesis of functionalized alkenes. The synthesis of 3-substituted ethyl acrylates and acrylonitriles, which are used as monomers in polymerization, were successfully carried out by the reaction of triethyl phosphonoacetate or cyanomethanephosphonate, respectively, with various aldehydes with activated Ba(OH)2 as the catalyst in the presence of dioxane solvent at 343 K (294). As was observed for other basic solid... 

Studies of the reactivity of phosphite esters towards substrates other than metal ions also continue to be of wide interest. Aspects of the reactivity of phosphites, e.g., trimethyl phosphite, towards a-diketones and o-quinones have been reviewed. " The Michaelis-Arbuzov reaction has found further applications in synthesis. An efficient synthesis of a phosphonoacetate-trilactoside conjugate relies upon the Michaelis-Arbuzov reaction of bromoacetamide with... 

Bojilova, A., Nikolova, R., Ivanov, C., Rodios, N. A., Terzis, A., Raptopoulou, C. P. A comparative study of the interaction of salicylaldehydes with phosphonoacetates under Knoevenagei reaction conditions. Synthesis of 1,2-benzoxaphosphorins and their dimers. Tetrahedron 1996, 52, 12597-12612. 

Ethyl phosphonoacetate reacts with 3-keto-substituted thiophenes to give 81 which are precursors to bridged dithienylethylenes such as 82. The synthesis of a-ylidene-y-amidobutyronitriles, RCONH(CH2)2C(CN) = CR R" (R = NPh2, r2 = R" rz Me R = R = Ph, R" = H, Me, Ph), has been achieved by the reaction of the phosphonates RC0NH(CH2)2CHCNP(0)(0Et)2 (R = NPh2, Ph) with ketones. The enantioselective synthesis of allenecarboxylates is accomplished by asymmetric Homer-Wadsworth-Emmons reaction of chiral phosphonoacetate-... 

Barium hydroxide [33, 34] is a strong base which has been employed not only in organic synthesis but also for other purposes. The commercially available octahydrate, l a(OI 1)2 8 11,/) is often used after transformation to the anhydrous form at 200-500 °C. Dehydrated Ba(OH)2 activated at 200°C is denoted C-200. It is known to be a heterogeneous basic catalyst in the Horner-Wadsworth-Emmons (HWE) reaction of triethyl phosphonoacetate (69) with aldehydes 70 to give the 3-substituted ethyl acrylates 71 (Scheme 5.13) [35]. The HWE reaction proceeds at 70 °C in 1,4-dioxane with a small amount of water. The yields of products 71 are usually better than those provided by typical basic catalysts such as NaOH or... 

Hamilton. C.J., and Roberts, S.M., Synthesis of fluorinated phosphonoacetate derivatives of carbocyclic nucleoside monophosphonates and activity as inhibitors of HIV reverse transcriptase. J. Chem. Soc.. Perkin Trans. 1, 1051, 1999. 

Dawson. N.D.. and Burger, A., Some alkyl thiazolephosphonates, J. Am. Chem. Soc., 74, 5312, 1952. Fiszer. B.. and Michalski, J Synthesis of organophosphorus compounds based on phosphonoacetic ester and its analogs. Addition of phosphonoacetic ester, alkylated phosphonoacetic esters, and phosphonoacetic nitrile to a.P-unsaluraled esters and nitriles, Rocz. Chem., 28, 185, 1954. 

Kim, D.Y., Choi, J.S., and Rhie, D.Y., P-C bond cleavage of triethyl 2-fluoro-3-oxo-2-phosphonoacetates with magnesinm chloride. A synthesis of a-fluoro-P-keto esters, Synth. Commun., Tl, 1097, 1997. 

Pudovik, A.N., and Lebedeva, N.M.. New method of synthesis of esters of phosphonic and thiophos-phonic acids. Part 23. Addition of phosphonoacetic ester, phosphonoacetone, and its homologs to unsaturated compounds, Zh. Obshch. Khim., 25, 1920, 1955 Chem. Abstr., 50, 8442c. 1956. 

Diethyl l-(ethoxycarbonyl)methylphosphonate was obtained for the first time by A. E. Arbuzov and Dunin by the reaction of ethyl bromoacetate with triethyl phosphite. " Subsequently, the Arbuzov-Dunin method was successfully extended for the synthesis of the alkyl esters of differently substituted dialkyl phosphonoacetates (R = Me, Et, /-Pr, n-Pr, n-Bu, /-Pent, n-Pent, n-... 

Synthesis of labeled phosphonoacetates proceeds on heating trialkyi phosphites with methyl or ethyp5 [l- C]bromoacetate, methyl [2- C]bromoacetate, ethyl [2- C]bromoacetate, ethyl [2- C]bromoacetate, and methyl or ethyl[ l- C]bromoacetate. Dialkyl l-(methoxy-carbonyl)methyl[l,l- H2]phosphonates are prepared from trialkyi phosphites and ethyl [2,2- H2]bromoacetate ° or by simple treatment of the nondeuterated phosphonoacetate with H2O in the presence of K2(X),." 5... 

Several innovations have significantly extended the scope and synthetic utility of the classical Michaelis-Becker phosphonoacetate preparation. Eor example, the coupling of the Michaelis-Becker and Homer-Wadsworth-Emmons reactions for the synthesis of a-substituted acrylic acids represents a useful modification. According to Scheme 8.10, Michaelis-Becker alkylation of a dialkyl phosphite with a haloacetic acid in the presence of 3 eq of a base (one to neutralize the carboxyl group, one to form the phosphite conjugate base, and one to deprotonate the initially formed alkylation product) leads to the phosphoryl-stabilized anion directly. Treatment of the anion... 

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