Phosphonous esters, synthesis

Campbell, D. A., and Bermak, J. C. (1994) Phosphonate ester synthesis using a modified Mitsunobu condensation. J. Org. Chem. 59, 658-660. 

Pergament, I., and Srebnik, M., Hydroboration of unsaturated phosphonic esters. Synthesis of borono-phosphonates and trisubstituted vinylphosphonates. Org. Lett., 3, 217, 2001. 

Schrader, T., Kober, R., and Steglich. W., Synthesis of l-aminophosphonic acid derivatives via (acylimino)phosphonic esters. Synthesis. 372, 1986. 

Schaumann. E.. and Fittkau, S., Synthesis and Wittig-Homer reactions of 1-(functionallyjsubstituted 2,2-dimethylpropanephosphonic esters (1-fert-butyl-substituted phosphonic esters). Synthesis, 449, 1983. 

Seki, M., and Matsumoto, K., A facile preparation of amino(diethoxyphosphoryl)acetic esters. Transformation of phosphoranes to phosphonic esters. Synthesis, 580, 1996. 

Texier-Boullet F, Lequitte M (1986) An unexpected reactivity of simple heterogeneous mixture of y-alumina and potassium fluoride 1-hydroxyalkane phosphonic esters synthesis fixrm non-activated ketones in dry media . Tetrahedron Lett 27 3515-3516... 

Despite several attractive features in this method of direct halogen introduction and the obvious applications in the synthesis of deoxy sugars, its uses have not been further exploited by other groups of workers. Some new related methods have become available which reportedly eliminate the difficulties previously encountered such as rearrangement, unreactivity due to steric hindrance, and phosphonate ester formation. The reaction is based on the observation (28) that triethylphosphine reacts with ethanol and carbon tetrachloride to give ethyl chloride, chloroform, and triethylphosphite. In a new adaptation (76, 77) of this... 

The synthesis and surface-active properties of higher hydroxyalkanediphos-phonates are discussed in Ref. 67. Phosphorus-containing betaines as hydrolytically stable surfactants, free from alkali salt impurities, were prepared by a reaction of amidoamines and equimolar amounts of phosphonate esters with 1.5-2 eq of formaldehyde at 60-140°C in a polar solvent [72]. 

Among phosphonate esters (170) used in olefin synthesis were those with R = S-CeHi-Br-/ , S02 C6H4-Br-A CO-NHR, and S CHa CEi-XHa. The allyl vinyl thio-ethers (171) obtained using the last of these gave a-allyl-aldehydes on pyrolysis in the presence of red mercuric oxide. 

In a paper concerned primarily with the use of epoxyalkylphosphonates in the synthesis of heterocyclic compounds, the (epoxyalkyl)phosphonic esters have been obtained, accompanied by (2-oxoalkyl)phosphonic esters (81) in the reaction... 

The perturbation converting the NH to a CH2 was calculated in a similar manner and in advance of inhibitor synthesis. In this case, the AGaq and AGcom were -2.4 0.28 and -2.72 0.84 kcal/mol, respectively, which predicted a AAGbind to be -0.3 kcal/mol. This result is in close agreement with the experimental result of. -0.1 kcal/mol, determined after the prediction. Since, like the phosphonate ester, the phosphinate lacks the hydrogen bond to the carbonyl of Alai 13, it should be less potent than the phosphanamide inhibitor. However, it is more potent than the phosphonate ester due to more favorable desolvation (AGsoi = -2.4 0.3) and reduced electrostatic repulsion. 

Burkhouse, D. and Zimmer, H., Novel synthesis of 1-alkoxy-l-arylmethane-phosphonic acid esters, Synthesis, 330, 1984. 

Hamilton, R., Walker, B., and Walker, B.J., A convenient synthesis of N-pro-tected diphenyl phosphonate ester analogues of ornithine, lysine and homolysine, Tetrahedron Lett., 34, 2847, 1993. 

Chodkiewicz, W., One-pot synthesis of chiral phosphonous esters, conversion into asymmetric phosphines, ]. Organomet. Chem., 273, C55, 1984. 

In a detailed study on phosphonate diester and phosphonamidate synthesis, Hirschmann, Smith, and co-workers reported that pyrophosphonate anhydrides may be produced as side products during conversion of phosphonate monoesters into phosphonochloridates. 72 They recommended adding the phosphonate monoester to a solution of the chlorinating agent (thionyl chloride or oxalyl chloride) to minimize formation of the less reactive anhydrides. They also found that addition of tertiary amines (e.g., TEA) to the phosphonochloridates, prior to addition of the alcohol or amine component, results in formation of a phospho-nyltrialkylammonium salt that is more reactive than the corresponding phosphonochloridate and leads to better yields of the phosphonate esters and amides. 

Changing the ester to a related phosphonate group allows the synthesis of biologically important [10] 2-amino-1-hydroxy phosphonic esters 7. However, the selectivities and especially the yields are significantly lower compared to the corresponding acrylates [11]. 

Scheme 4. Synthesis of 2-amino-l-hydroxy phosphonic esters via the AA.

Phosphonate esters can be deprotonated with sodium hydride or alkoxide anions to give enolate-type anions that react well with aldehydes or ketones to give -alkenes. Alkene-forming reactions with phosphonates are called Horner-Wadsworth-Emmons (or Horner-Emmons, Wadsworth-Emmons, or even Horner-Wittig) reactions. This example is a reaction that was used by some Japanese chemists in the synthesis of polyzonimine, a natural insect repellent produced by millipedes. 

Lukszo, J. and Tyka, R., New protective groups in the synthesis of 1-amino-alkane-phosphonic acids and esters. Synthesis, 2.19, 1977. 

Senten K, Daniels L, Van der Veken P, De Meester 1, Lambeir 69. A-M, Scharpe S, Haemers A, Augustyns K. Rapid parallel synthesis of dipeptide diphenyl phosphonate esters as inhibitors of dipeptidyl peptidases. J. Comb. Chem. 2003 5 336-344. 70. 

The application of the Michael addition of phosphonate esters in the synthesis of coronafacic acid was reported by Shibasaki and coworkers and is outlined in Sch. 61 [89]. The Michael adduct ent-427 was prepared in 94 % ee in the same fashion as its enantiomer 427 (Sch. 59) by employing a catalyst prepared from (5)-BINOL. 

Reports on arylphosphonates include the synthesis and resolution of new racemic phosphonic acid methyl (213) and dimethyl esters (214) via cinchonium salts (Scheme 56). The absolute configuration of the phosphonic ester products was also established. 

The synthesis of tetraarylsilanes via Wurtz cross-coupling of bromoarenes and SiCU is a short and efficient route to tetraarylsilanes. Four conjugated units like biphenyl or naphthalene can be attached to the central silicon atom in high yield, but in the case of donor-substituted stilbenoid oligomers, this method gave only poor results [12]. For the preparation of tetrahedral silanes with phenylenevinylene chromophores, the convergent step was not performed on the central silicon atom but on a tetra- -tolylsilane (lb) functionalized with four phosphonic esters. The advantage of this approach is the additional extension of the n-system in the final step. 

Table 15 Synthesis of Disubstituted Alkenes by Trifluoroethyl Phosphonate Esters in THF...

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