New di-, tri-, and tetraphosphonic acids were synthesized starting from four o-hydroxymethyl phenol derivatives and obtained in three steps in good overall yield. The phosphonic acids were isolated and purified using semi-preparative C18 HPLC column. The new compounds were characterized using different spectroscopic methods (1H, 13C, and 31P NMR; ESI MS; and MSn, IR). GRAPHICAL ABSTRACT

/pdf/synthesis-of-new-benzylic-di-tri-and-tetraphosphonic-acids-26hw6eqqbp.pdf

Synthesis of New Benzylic Di-, Tri-, and Tetraphosphonic Acids as Potential Chelating Agents

The utilization of phosphirenium ions is presented; optimized and broadened three-membered ring construction is described together with the use of these ions as efficient pre-catalysts for metal-free carbonyl reduction with silanes. Full characterization of the phosphirenium ions is presented, and initial experimental and computational mechanistic studies indicate that these act as a "masked phosphenium" source that is accessed via ring opening. Catalysis proceeds via associative transfer of {Ph2P+} to a carbonyl nucleophile, H-SiR3 bond addition over the C=O group, and associative displacement of the product by a further equivalent of the carbonyl substrate, which completes the catalytic cycle. A competing off-cycle process leading to vinyl phosphine formation is detailed for the hydrosilylation of benzophenone for which an inverse order in [silane] is observed. Experimentally, the formation of side products, including off-cycle vinyl phosphine, is favored by electron-donating substituents on the phosphirenium cation, while catalytic hydrosilylation is promoted by electron-withdrawing substituents. These observations are rationalized in parallel computational studies.

Phosphirenium Ions as Masked Phosphenium Catalysts: Mechanistic Evaluation and Application in Synthesis.

A facile method of synthesis of functionally substituted P(IV) derivatives―dialkyl(diaryl)(2-hydroxybenzyl) phosphine oxides―by the reaction of 2-ethoxy-2,3-dihydro[d][1,2]oxaphosphole 2-oxide with organomagnesium compounds, which allows wide variation of substituents on the phosphorus atom was developed.

2-Ethoxy-2,3-dihydro[d][1,2]oxaphosphole 2-oxide in the synthesis of dialkyl(diaryl)(2-hydroxybenzyl)phosphine oxides

1,2-Heteraphosphacyclanes have drawn the attention of synthetic chemists due to their association with various biological activities and their unusual properties. The focus of this chapter is on the synthetic approaches to heterocyclic compounds of this type, which are principally different from the compounds with three-membered, four-membered and larger ring size and differ greatly depending on the nature of the heteroatom in the ring.

Synthetic Approaches to 1,2-Heteraphosphacyclanes

Irradiation of the three isomeric chlorobenzylphophonic acids in aqueous buffer led to a pH-dependent photochemistry. Under acidic conditions (pH = 2.5), photocleavage of the Ar–Cl bond occurred and a phenyl cation chemistry resulted. Under basic conditions (pH = 11), a photoinduced release of the chloride anion followed by the detachment of the metaphosphate anion gave α,n-didehydrotoluene diradicals (α,n-DHTs), potential DNA cleaving intermediates. At a physiological pH (pH = 7.2), both a cationic and a diradical reactivity took place depending on the phosphonic acid used. It is noteworthy that the complexation exerted by a monosaccharide (glucose or methylglucopyranoside) present in solution induced an exclusive formation of α,n-DHTs. The mechanistic scenario of the different photoreactivities occurring when changing the pH of the solution and the role of the various intermediates (phenyl cations, diradicals, etc.) in the process was studied by computational analysis.

Sugar-Assisted Photogeneration of Didehydrotoluenes from Chlorobenzylphosphonic Acids.

Interaction of trialkylphosphites with o-hydroxybenzyl alcohol and 2-methoxymethyl-6-methylphenol

On the basis of a study of the reaction of triethyl phosphite with o-hydroxybenzyl alcohol by methods of IR and NMR spectroscopy and the kinetic data, it was established that the reaction is first order and proceeds according to the classical scheme of the Arbuzov rearrangement, with intermediate formation of a quasiphosphonium-type complex.

Mechanism of the interaction of o-hydroxybenzyl alcohol with trialkyl phosphites

1.

2-Oxo-2-alkoxy-R-1-oxa-2-phosphaindans are formed when trialkyl phosphites are reated with o-hydroxybenzyl alcohol and 2-methoxymethyl-6-methylphenol.




2.

The reaction of o-hydroxybenzyl alcohol with mono- and dichlorophosphites leads to the formation of 2-oxo-2-alkoxy-1-oxa-2-phosphaindans in low yield.

Reaction of trialkyl phosphites with o-hydroxybenzyl alcohol and its derivatives

N-Acetoxymethyldiethylamine reacts with tetraethyldiamidophenylphosphonite and diethylamidodiphenylphosphinite, and N-acetoxymethylbenzamide with tetraethyldiamidophenylphosphonite at the phosphorus atom only to form Arbuzov reaction products. The reaction of N-acetoxymethylacetamide with tetraethyldiamidophenylphosphonite and diethylamidodiphenylphosphinite, and the reaction of N-acetoxymethylbenzamide with diethylamidodiphenylphosphinite proceed at two reaction centers at the phosphorus atom to form the Arbuzov reaction products, and at the nitrogen atom to form acetoxyphosphinites (phosphonites) and N-diethylaminomethylamides.

Dual reactivity of diphenylphosphinous and phenylphosphonous acid amides in reactions with N-acetoxymethyl-substituted diethylamine, benzamide, and acetamide

Mono-, di-, and triamidophosphites react with N-acetoxymethylacetamide and N-acetoxymethylbenzamide at the phosphorus atom and at the nitrogen atom. In the reactions with N-acetoxymethylacetamide the fraction of the product of attack at the nitrogen atom is higher than in the reactions with N-acetoxymethylbenzamide.

A. B. Ageeva

Papers

Interaction of trialkylphosphites with o-hydroxybenzyl alcohol and 2-methoxymethyl-6-methylphenol

Mechanism of the interaction of o-hydroxybenzyl alcohol with trialkyl phosphites

Reaction of trialkyl phosphites with o-hydroxybenzyl alcohol and its derivatives

Dual reactivity of diphenylphosphinous and phenylphosphonous acid amides in reactions with N-acetoxymethyl-substituted diethylamine, benzamide, and acetamide

Reaction of N-acetoxymethylacetamide and N-acetoxyme thylbenzamide with ester-amides and amides of phosphorous acid