Alkenylphosphonates synthesis

Isoxazolmes are good preciusors of a,fi-unsatiuated ketones.This transformadon ii nsefid for synthesis of polyenes. For example, nitnle oxide cycloaddidon chemistry is used tc prepare4-oxo-2-alkenylphosphonates, which are useful to synthesize a long polyethylenic unii via Woodworth-Errunons olefinadon fEq. 8.66. ... 

In the asymmetric addition to alkenylphosphonate 33 (Eq. 2) [25], the yield is dependent on the amount of water present. The combination of boroxine and water (1 equiv. relative to boron) gave a high yield of the desired product 34, with 96% enantiomeric excess. The alkylphosphonate 34 can be used as a chiral building block for the synthesis of optically active alkenes, using a Horner-Emmons type of reaction. 

Hamden, M.R., Parkin, A., Parratt, M.J., and Perkins, R.M., Novel acyclonucleotides. Synthesis and antiviral activity of alkenylphosphonic acid derivatives of purines and a pyrimidine, J. Med. Chem., 36, 1343, 1993. 

Benayoud. E, Chen, L.. Moniz. G.A.. Zapata, A.J., and Hammond, G.B., Synthesis of t/.-fluoro-P,"/-alkenylphosphonates and conjugated fluoroenynes from a common intermediate (a-fluoropropar-gyljphosphonate. Tetrahedron. 54, 15541, 1998. 

Petrov, K.A., Raksha, M.A., Korotkova, V.P., and Shmidfi E., Synthesis and properties of alkenylphosphonic derivatives. Part 4. P-Aldo phosphonic esters, Zh. Obshch. Khim., 41, 324, 1971 7. Gen. Chem. USSR (Engl. Transl.), 41, 319, 1971. 

Wada, E., Kanemasa, S., and Tsuge, O., New synthesis of 2-oxo-3-alkenylphosphonates and hetero Diels-Alder reactions with vinyl ethers leading to 5-substituted 2-phosphinyl-2-cyclohexen-l-ones, Bull. Chem. Soc. Jpn., 62, 860, 1989. 

Ohler, E., and Kotzinger, S., Thermal reanangement of trichloroacetimidic esters of allylic a-hydroxyphosphonates. A convenient way to (3-amino-1-alkenylphosphonic acids, Synthesis, 497, 1993. 

Oxo-2-alkenylphosphonates. A synthesis of this class of apparently useful compounds involves nitrile oxide cycloaddition with allylic phosphonates, conversion of the resulting isoxazolines to the conjugated oximes, and hence to the enones. The last step is readily achieved by the use of TiCl,. 

E. Synthesis of Alkenylphosphonic Acids Using the Wittig Reaction... 

Scheme 11 indicates the usefulness of salts derived from Wittig ylide reagents and anhydrides of perfluorocarboxylic acids in the synthesis of fluorinated alkenylphosphonic diesters (127), often together with (epoxyalkyl)phosphonic diesters (128)(Rf = CF3 or... 

The addition of a nitroalkane to an alkenylphosphonic diester is exemplified by the interaction of nitromethane with diethyl ethenylphosphonate in the presence of NaOEt, when the product is diethyl (3-nitropropyl)phosphonate and by a similar addition to 1,1-bis(diethoxyphosphinoyl)ethane . In the initial stages of a synthesis of (4,5,6-trihydroxy-3-oxohexyl)phosphonic acid, the nitro sugar 76 was made to add to dibenzyl ethenylphosphonate, but the resultant (3-nitropropyl)phosphonic dibenzyl ester 77 was then used without isolation. ... 

In 2013, the synthesis of phosphaisocoumarins is achieved by Miura and coworkers via Rh(III)-catalyzed oxidative annulation of phenylphosphonic acids with alkynes (Scheme 6.25a) [40]. Shortly after, Lee and coworkers reported a similar result using phenylphosphinic or alkenylphosphonic acids to afford phosphaisocoumarins in good yields (Scheme 6.25b) [41]. 

Hayashi T, Senda T, Takaya Y, Ogasawara M (1999) Rhodium-Catalyzed asymmetric 1,4-addition to 1-alkenylphosphonates. J Am Chem Soc 121 11591-11592 Giordano C, Castaldi G (1989) First asymmetric synthesis of enantiomerically pure (1R,2S)-(-)-(l,2-Epoxypropyl)phosphonic acid (Fosfomycin). J Org Chem 54 1470-1473... 

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