Synthesis of α-functionalized phosphonates from α-hydroxyphosphonates

Lipase-Catalyzed Kinetic Resolution of Dimethyl and Dibutyl 1-Butyryloxy-1-carboxymethylphosphonates

The main objective of this study is the enantioselective synthesis of carboxyhydroxyphosphonates by lipase-catalyzed reactions. For this purpose, racemic dimethyl and dibutyl 1-butyryloxy-1-carboxymethylphosphonates were synthesized and hydrolyzed, using a wide spectrum of commercially available lipases from different sources (e.g., fungi and bacteria). The best hydrolysis results of dimethyl 1-butyryloxy-1-carboxymethylphosphonate were obtained with the use of lipases from Candida rugosa, Candida antarctica, and Aspergillus niger, leading to optically active dimethyl 1-carboxy-1-hydroxymethylphosphonate (58%–98% enantiomeric excess) with high enantiomeric ratio (reaching up to 126). However, in the case of hydrolysis of dibutyl 1-butyryloxy-1-carboxymethylphosphonate, the best results were obtained by lipases from Burkholderia cepacia and Termomyces lanuginosus, leading to optically active dibutyl 1-carboxy-1-hydroxymethylphosphonate (66%–68% enantiomeric excess) with moderate enantiomeric ratio (reaching up to 8.6). The absolute configuration of the products after biotransformation was also determined. In most cases, lipases hydrolyzed (R) enantiomers of both compounds.

Cinchona-Diaminomethylenemalononitrile Organocatalyst for the Highly Enantioselective Hydrophosphonylation of Ketones and Enones

The use of diaminomethylenemalononitrile (DMM) organocatalyst to promote the challenging 1,2-hydrophosphonylation of simple ketones and enones, which are also called α,β-unsaturated ketones, is proposed and validated. This reaction provided the corresponding chiral α-hydroxy phosphonates in high to excellent yields and with enantioselectivity up to 96% ee.

Synthesis, Spectroscopic Characterization, and In Vitro Antibacterial Evaluation of Novel Functionalized Sulfamidocarbonyloxyphosphonates

Several new sulfamidocarbonyloxyphosphonates were prepared in two steps, namely carbamoylation and sulfamoylation, by using chlorosulfonyl isocyanate (CSI), α-hydroxyphosphonates, and various amino derivatives and related (primary or secondary amines, β-amino esters, and oxazolidin-2-ones). All structures were confirmed by ¹H, ¹³C, and ³¹P NMR spectroscopy, IR spectroscopy, and mass spectroscopy, as well as elemental analysis. Eight compounds were evaluated for their in vitro antibacterial activity against four reference bacteria including Gram-positive Staphylococcus aureus (ATCC 25923), and Gram-negative Escherichia coli (ATCC 25922), Klebsiella pneumonia (ATCC 700603), Pseudomonas aeruginosa (ATCC 27853), in addition to three clinical strains of each studied bacterial species. Compounds 1a⁻7a and 1b showed significant antibacterial activity compared to sulfamethoxazole/trimethoprim, the reference drug used in this study.

Synthesis and Reactions of α-Hydroxyphosphonates

This review summarizes the main synthetic routes towards α-hydroxyphosphonates that are known as enzyme inhibitors, herbicides and antioxidants, moreover, a number of representatives express antibacterial or antifungal effect. Special attention is devoted to green chemical aspects. α-Hydroxyphosphonates are also versatile intermediates for other valuable derivatives. O-Alkylation and O-acylation are typical reactions to afford α-alkoxy-, or α-acyloxyphosphonates, respectively. The oxidation of hydroxyphosphonates leads to ketophosphonates. The hydroxy function at the α carbon atom of hydroxyphosphonates may be replaced by a halogen atom. α-Aminophosphonates formed in the nucleophilic substitution reaction of α-hydroxyphosphonates with primary or secondary amines are also potentially bioactive compounds. Another typical reaction is the base-catalyzed rearrangement of α-hydroxy-phosphonates to phosphates. Hydrolysis of the ester function of hydroxyphosphonates leads to the corresponding phosphonic acids.

Evaluation of ecotoxicological impact of new pyrrole-derived aminophosphonates using selected bioassay battery

Six new dimethyl N-arylamino(2-pyrrolyl)methylphosphonates 2a-f were synthesized by the modified aza-Pudovik reaction. Their ecotoxicological impact using battery of bioassay was assessed using Microtox and Ostracodtoxit tests as well as phytotoxicity towards two plants, dicotyledonous radish (Raphanus sativus) and monocotyledonous oat (Avena sativa) following the OECD 208 Guideline. Ecotoxicological properties of compounds 2a-f in aspect of acute and chronic toxicity were evaluated using Heterocypris incongruens and Aliivibrio fisheri tests. The obtained results showed that tested aminophosphonates 2a-f have moderate-to-high phyto- and ecotoxicological impact. They are toxic for both plants but more toxic against dicotyledonous. The investigated compounds showed important ecotoxicity against Heterocypris incongruens crustaceans and Aliivibrio fisheri bacteria. It was found that the substituents of the phenyl ring plays a key role in the degree of toxicity. Results showed that investigated compounds are ecologically toxic and that any of their application should be implemented with care.

Organocatalytic Hydrophosphonylation Reaction of Carbonyl Groups

This revision is covering the limited examples reported for a pivotal strategy in the formation of C-P bonds such as the asymmetric organocatalytic hydrophosphonylation of carbonyl groups (Pudovik reaction). The scope and limitations, and the proposed mechanisms for the scarce different possibilities of asymmetric induction are also shown. The recent evolution and future trends of this undeveloped approach are commented.

Highly active group 11 metal complexes with α-hydrazidophosphonate ligands

Unprecedented α-hydrazidophosphonate group 11 metal complexes have been prepared, with various coordination modes of ligands to metal atoms. They present an excellent cytotoxic activity in HeLa (cervical carcinoma) and A549 (lung carcinoma) cell lines, with IC₅₀values among the lowest found in silver or copper complexes.

Organocatalytic decarboxylative aldol reaction of β-ketoacids with α-ketophosphonates en route to the enantioselective synthesis of tertiary α-hydroxyphosphonates

γ-Aroyl tertiary α-hydroxyphosphonates with a chiral quaternary centre were synthesized via a facile organocatalyzed decarboxylative aldol reaction between β-ketoacids and α-ketophosphonates.

Synthesis and ecotoxicological impact of ferrocene-derived amino-phosphonates using a battery of bioassays

Ferrocene-derived aminophosphonates showed their various ecotoxicological impact on terrestrial higher plants, freshwater ostracods and marine bacteria.

Enantioselective magnesium-catalyzed transformations

This review updates the major progress in the field of enantioselective transformations promoted by chiral magnesium catalysts, covering the literature since 2007, illustrating the power of these green catalysts to promote many types of reactions.

Organocatalytic enantioselective hydrophosphonylation of aldehydes

We report our results concerning the first squaramide-catalysed hydrophosphonylation of aldehydes. In all cases, the reactions proceeded smoothly and cleanly under mild reaction conditions rendering final α-hydroxy phosphonates in very good yields and high enantioselectivities. It is one of the few organocatalytic examples of this reaction using aldehydes. It is the first time that diphenylphosphite (1e) has been successfully employed in a chiral Pudovik reaction with aldehydes, in contrast to the dialkylphosphites used in previously published procedures, extending the generality of this asymmetric methodology.

Synthesis of non-racemic α-hydroxyphosphonates via asymmetric phospho-aldol reaction

It has been more than 50 years since the first phospho-aldol reactions of dialkyl phosphites were reported. These efficient P-C bond-forming reactions have become the cornerstone of methods for the synthesis of α-hydroxyphosphonates and, by numerous available substitution reactions, the synthesis of other α- and γ-substituted phosphonates and phosphonic acids. Much of the interest in α- and γ-substituted phosphonates and phosphonic acids has been stimulated by reports of their biological activity, which is often dependent upon their absolute and relative stereochemistry. In this chapter, we review diastereoselective and enantioselective additions of dialkyl phosphites to aldehydes and ketones, otherwise called the phospho-aldol, Pudovik or Abramov reactions.

α-Azido bisphosphonates: synthesis and nucleotide analogues

The first examples of α-azido bisphosphonates [(RO)(2)P(O)](2)CXN(3) (1, R = i-Pr, X = Me; 2, R = i-Pr, X = H; 3, R = H, X = Me; 4, R = H, X = H) and corresponding β,γ-CXN(3) dGTP (5-6) and α,β-CXN(3) dATP (7-8) analogues are described. The individual diastereomers of 7 (7a/b) were obtained by HPLC separation of the dADP synthetic precursor (14a/b).