Alkenylphosphonic acids

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. 

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. 

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

Alkenylphosphonic acid (1) can be synthesized aeeording to the following seheme [385-388] ... 

The polymerization of 1 can be started thermically, with radicals, or by light [385,390,391]. However, since only oligomers were observed, those homopolymerizations are of academic interest only. 1 has been copolymerized with vinyl chloride and vinyl acetate [392], initiated by redox initiators in emulsion. Copolymers of this monomer are also available by hydrolysis of copolymers containing derivatives of 1-alkenylphosphonic acid, such as dichlorides [392-394] or diesters [395]. Copolymers are also described with acrylonitrile, acrylic amide, N-vinylacetamide, and N-vinylpyrrolidone they are particularly interesting for textile dying, tanning techniques and water separating membranes [396-399]. 

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]. 

Organoboron reagents are particularly well suited for 1,4-additions of aryl and vinyl groups to enones. Hayashi et al. developed a highly enantioselective Rh(I)/ BINAP-catalyzed 1,4-addition of phenylboronic acid to cyclic and acyclic enones [24] (Scheme 7.5) and 1-alkenylphosphonates [25]. 

Alkenylphosphonates (226) can be prepared by regioselective addition of monoesters of phosphonic acid (227) to alkynes in the presence of Hg(OAc)2/ BFs OEt2 (Scheme 61). ... 

The first successful preparation of phosphorus-containing heterocyclic fatty acid derivatives has been presented. Reaction of cx-keto allene (379) with trimethyl phosphite gave oxaphosphole derivative (380). Similar transformations with a-keto and a-chloro-ot-ketoallenes (381) and (382) led to the formation of alkenylphosphonates (383) and (384), respectively (Figure 64) ... 

Conjugate additions. Arylborates generated in situ from ArBr are effective as asymmetric addends to enones in the presence of a Rh-complex derived from BINAP and (acac)2Rh(C2H4)2. They give excellent chemical yields and ee (>91%, often 99%). In these processes (such as conjugate addition to alkenylphosphonates ), the use of arylboroxines (ArBO), instead of arylboronic acids is advantageous because catalytic activity of the Rh complex decimated by large amount of water can be avoided. 

Pyrolysis (in boiling toluene) of the sulphoxide obtained from a dialkyl (l-phenylth> ioalkyl)phosphonate (339) and 3-chloroperoxybenzoic acid affords an alkenephosphonic diester, and subsequent work showed that the sequence was adaptable to the production of chiral esters of alkenylphosphonic diester with optical purities of not less than 93%. Use of the ( S )p-phosphonic amide 340 afforded a mixture of the (E)-(S)p- and (Z)-(S)p-stereoisomers (341), separable by chromatographic methods. ... 

The use of esters of a (substituted-methyl)phosphonic acid to provide the carbanion site next to phosphoryl phosphorus was a natural step forward. The most successful development has been the use of the carbanion 346 derived from esters of methylenebisphospho-nic acid (or its monoalkylated derivatives). The anion 346 reacts with an aldehyde to afford the alkenylphosphonic diester 347 (R = Et, Ph, PhCH—CH, 2-thienyl, 2-pyridinyl, etc,) ". Use of the protected 3-pyridinylcarboxaldehyde 348 allowed the preparation of the ester 349, which, after reduction of the C=C bond and hydrolysis, afforded the phosphonic acid 350 Such reactions have also been carried out under phase-transfer condi-tions. Reactions between the lithium salt of the ester 351 and benzaldehyde or but-2-enal give the (alk-1 -enyl)phosphonic esters 352 and 353 in the ratio 1 4 the lithium salts 354 and 355 are formed concomitantly in the ratio 4 1. ... 

Esters and other derivatives of alkenyl- and alkynyl-phosphonic acids, and of the correspondingly unsaturated phosphinic acids, undergo a wide range of addition and cycloaddition reactions which will be considered more fully in Chapter 6. These reactions include applications of the Diels-Alder reaction to yield carbocyclic phosphonic acids based on mono- and poly-cyclic ring systems, some of which are precursors to other aromatic phosphonic acids. A typical example of this procedure is the addition of dimethyl (bromoethynyl)phosphonate to 2,3-dimethylbutadiene elimination of HBr from the 1 1 cycloadduct, using Et3N, affords dimethyl (2,3-dimethylphenyl)phosphonate. The addition of carbenes to alkenylphosphonic derivatives yields those of cyclopropylphos-phonic acids. ... 

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 epoxidation of halogenated alkenylphosphonic esters with trifluoroperoxyacetic acid yields unstable halogenated (epoxyalkyl)phosphonic esters, which isomerize rapidly by a 1,2-shift of halogen. The isomerization occurs for both 1,2-epoxyalkyl and 2,3-epoxy alkyl compounds, but in some cases the rearrangement is not regiospecific and affords both ketonic and aldehydic products ... 

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. ... 

Alkene-,alkyne-,aryl-phosphonic and phosphinic acids.-(of-Stannylalkyl)phosphonic acid diesters have been employed to prepare alkenylphosphonic diesters. Treatment of the tin compounds (251) (generated in situ) with an aldehyde R CHO at -70 yielded a mixture of ( ) and (Z) isomers of (252), the proportions being controlled essentially by... 

The asymmetric conjugate addition reaction has been applied to a,P-unsaturated amides,alkenylphosphonates, and ethenesulfonamides. Hayashi and co-workers have also applied the standard reaction conditions to nitroalkenes. The reaction was found to be applicable to a variety of arylboronic acids. The reaction was also extended to acyclic nitroalkenes without loss of selectivity, but not to nitrocycloheptene or nitrocyclopentene. Interestingly, the thermodynamically less stable cis isomers, e.g., 266, were formed in the reaction of nitrocyclohexene (265) with a wide range of arylboronic acids, e.g., 254. The initial products could be readily converted to the more stable trans isomers by treatment with base. 

Hayashi has reported a wide range of reactions employing rhodium with chiral binaphthylphosphine ligands, for example in the asymmetric 1,4-addition of boronic acids and triarylboranes to various unsaturated starting materials a,p-unsaturated ketones, esters, 1-alkenylphosphonates, nitroalkenes and 5,6-dihydro-2(lH)-pyridinones. ... 

A highly regio- and stereoselective palladium(O) catalyzed addition of organo-boronic acids to 1,2-allenylphosphonates (134) in the presence of acetic acid forming tri- and tetrasubstituted l( )-alkenylphosphonates (135) has been reported (Scheme 47). ... 

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