Aryl phosphonates, synthesis

ARBUZOV MICHAELIS Phosphonale Synihesis Ni catalyzed phosphonate synthesis from phosphites and aryl halides Reaction of alkyl halides with phosphites proceeds without nickel salts... 

Scheme 37 Palladium- and nickel-catalyzed synthesis of aryl phosphonates...

An optimised solid-phase method for the generation of diverse a-amino-alkyl or -aryl phosphonates derived from peptides and polymer-assisted solution-phase parallel synthesis of dipeptide p-nitroanilides and dipeptide diphenyl phosphonates have been reported. A modular method for the construction of polypeptides containing the Phe-Arg phosphinic acid isostere has been described. A novel methodology for the solid-phase synthesis of phosphinic peptides has been developed in which the phosphorus-carbon bond was formed... 

Hanessian, S., Bennani, Y.L., and Herve, Y, A novel asymmetric synthesis of a- and P-amino aryl phosphonic acids, Synlett, 35, 1993. 

Guzman, A., Alfaro, R., and Diaz, E., Synthesis of aryl phosphonates by reaction of Grignard reagents with diethyl cyanophosphonate, Synth. Commun., 29, 3021, 1999. 

Yuan, C., Chen, S., Zhou, H., and Maier. L.. Studies on organophosphorus compounds. Part 75. A facile synthesis of l-(hydroxyamino)alkyl(or aryl)phosphonic acids. Synthesis, 955, 1993. 

K. A. Petrov et al.. Methods of synthesis of aryl phosphonic acids-, Russ. Chem. Revs., 1042, 1986. 

SCHEME 5.15 Asymmetric organocatalyzed synthesis of a-aryl phosphonates 48. 

Recently, Jakoby et al. [64,65] reported a synthesis of phosphonated polyphenylsulfone. This group has focused their efforts on two straightforward reactions for the synthesis of aryl phosphonic acids from brominated or iodinated aromatic starting materials. 

Scheme 5 Synthesis of aryl-phosphonates/phosphinates/phosphine oxides using faciie aryne reactivity.

A selective protection and deprotection of o/t/jo-functionalised aryl-phosphonates (447) have been reported by Marchand-Btynaert and co-workers. The key step of the developed synthesis consisted of the introduction of a phosphoryl group by an o/t/jo-metallation reaction from protected ort/zo-anisidine. Chemoselective deprotections have been investigated and mono-, bis-, and ter-deprotected aromatic derivatives have been obtained. A practical route to phosphorylated benzoxazoles (448) has been thus discovered (Scheme 154). ... 

A multitude of 2,3,5-trisubstituted furans are available via the Paal-Knorr condensation. As with the synthesis of disubstituted furans, the scope of this version of the reaction is broad and includes incorporation of aryl, alkyl, ester, and phosphonate substituents. 

Among /1-thiosubstituted organophosphorus compounds bearing chiral groups, phosphono methyl thiazolines (Sect. 2.2.1, Scheme 8) and o-sulfanyl aryl phos-phonamides or phosphinoxides (Sect. 3.3, schemes 20 and 21) have already been mentioned. As a complement to this, some recent synthesis of non racemic /1-sulfinyl phosphines and phosphonates and thiazolidinyl phosphonates are reported below. Moreover, some chiral )8-thio-substituted phosphines have been used as metal ligands in asymmetric catalysis and are listed in Sect. 5.3. 

A modification of the Pomeranz-Fritsch synthesis <1983JCXI3344> is used in the preparation of thieno[2,3- l-pyridine and its 2-substituted derivatives. An aryl aldehyde undergoes condensation with aminoacetaldehyde dimethyl acetal giving a Schiff base which cyclizes to form an imine product. The imine is treated with ethyl chloroformate followed by triethyl phosphate to form an intermediate carbonate-phosphonate, which then cyclizes to the thienopyr-idine product (Scheme 22) <2004S1935>. Very low product yields (2-17%) are obtained for alkyl- and phenyl-substituted thieno[2,3- ]pyridines however, the unsubstituted product and 2-halogenated derivatives give moderate yields (28-44%). 

Such direct couplings of silylated alkynes have been applied to the synthesis of a variety of aryl- and heteroarylethynyl phosphonates, available only in poor yields with classical routes (Table 10.7).125... 

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