Mild Arbuzov reactions of phosphonous acids

A very mild and simple method for the preparation of phosphinic acids from phosphonous acids through the intermediacy of silylalkyl phosphonites is described.     

Preparation of phosphinic acids: Michael additions of phosphonous acids/esters to conjugated systems.

A very mild and facile method for the preparation of phosphinic acids via Michael addition of phosphonous acids as well as esters, through an intermediate silyl alkyl phosphonite, to activated conjugated systems is described.     

Über eine Reaktion von o-Hydroxybenzylalkoholen mit Estern von Säuren des Phosphors mit der Koordinationszahl 3

Abstract

o-Hydroxybenzyl alcohol reacts with trimethyl phosphite under smooth conditions to o-hydroxyphenylmethane phosphonic acid dimethyl ester. This unusual reaction is of widest applicability. Derivatives of o-hydroxybenzyl alcohol independent of type, number or position of substituents in the ring, react with alkyl esters of phosphorous, phosphonous or phosphinous acids in an analogous process, forming the corresponding o-hydroxyphenylmethane phosphonic or phosphinic esters or phosphine oxides.     

Advances in Organophosphorus Chemistry Based on Dichloro(methyl)phosphane

Besides phosphorus trichloride and phosphane, dichloro(methyl)phosphane is gaining importance as a starting material for the synthesis of organophosphorus compounds. It provides ready access to phosphonic, phosphinic and phosphonous acid derivatives, as well as their secondary products. The synthetic and application potential of organophosphorus compounds—based on industrially produced dichloro(methyl)phosphane—is illustrated by means of numerous examples.     

Reaction of perfluoroalkyl grignard reagents with phosphorus trihalides: a new route to perfluoroalkyl-phosphonous and -phosphonic acids

The reaction of perfluoroalkyl Grignard reagents with phosphorus(III) halides was explored. In the process a new convenient, one-pot, high yield method for the synthesis of (perfluoroalkyl)phosphonic acids has been developed. Perfluoroalkyl Grignard reagents react with phosphorus trichloride or phosphorus tribromide to form (perfluoroalkyl)phosphonous dihalides. Hydrolysis gives the corresponding (perfluoroalkyl)phosphonous acids. Oxidation of the phosphonous acids with H(2)O(2) produces (perfluoroalkyl)phosphonic acids in 60-78% overall yields, based on the corresponding perfluoroalkyl iodide. The X-ray crystal structures of the toluidinium salts, [MeC(6)H(4)NH(3)](2)[C(2)F(5)PO(3)] and [MeC(6)H(4)NH(3)][C(8)F(17)P(O)(2)OH], are reported.     

Synthesis of phosphonic monoesters from phosphonous acids

Phosphonic monoesters are prepared in a two—step procedure by DCC—DMAP mediated esterification of phosphonous acids and oxidation of the resulting phosphonous monoester.     

A novel synthesis of bis-(α-hydroxyalkyl)phosphinic acids involving microwave irradiation

A simple, efficient, and general method has been developed for the synthesis of bis-(α-hydroxyalkyl)phosphinic acids from hypophosphorous acid using microwave irradiation. Bis-(α-hydroxyalkyl)phosphinic acids were obtained in high yield under mild conditions by reaction of hypophosphorous acid with aldehydes under microwave irradiation.     

Neue Methoden zur Chlorierung von Organophosphorverbindungen mit P?H-Funktionen

New Methods for the Chlorination of Organophosphorus Compounds with P? H-Functions Starting from compounds containing a P? H bond, which are obtained by the addition of PH₃ to olefinic double bonds, novel methods are described for the synthesis of phosphonous and phosphinous acid chlorides as well as of phosphonic, phosphinic, and thiophosphinic chlorides. Compounds of the type RPH₂, R₂PH, R₂P(:O)H, and R₂P(:S)H (R = alkyl, cycloalkyl, aryl) are converted into the correspondent halogenated substances by means of C₂Cl₆ or PCl₅ without addition of base. Direct oxychlorination of prim. and sec. phosphines to phosphonic and phosphinic chlorides is achieved by SO₂Cl₂.     

Synthesis of some derivatives of bis (N,N-dialkylaminomethyl)phosphinic acids

Conclusions A number of derivatives of bis(N,N-dialkylaminomethyl)phosphinic acids have been obtained by the reaction of dialkylamines with esters and amides of bis(chloromethyl) phosphinic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1346–1348, June, 1967.     

Reaction of N-(Benzylkoxycarbonylamino) Benzylphosphonous Acid with Ethyl Orthoformate

Abstract

Peptide containing phosphinic acids are peptidomimetics which have been successfidly employed m the design of inhibitors of protease and ligase enzymes. These stable tetrahedral phosphorus species act by mimicking the tetrahedral mtemediates of the reactions catalyzed by these two groups of enzymes. Using this concept potent transition-state analogue inhibitors of a wide variety of protenses, as well as of some tigases have been developed and studied m some detail. One of the key problems m the synthesis of these peptidomimetics is the conversion of readily available N-blocked 1 -aminoakylphosphonous acids or their esters mto corresponding phosphinic acids.     

Rhodium‐Catalyzed Oxidative C–H Activation/Cyclization for the Synthesis of Phosphaisocoumarins and Phosphorous 2‐Pyrones

Rhodium‐catalyzed cyclization of phosphinic acids and phosphonic monoesters with alkynes has been developed. The oxidative annulation proceeds with complete conversion of phosphinic acid derivatives and allowed the atom‐economic preparation of useful phosphaisocoumarins with high yield and selectivity. The reaction is tolerant of extensive substitution on the phosphinic acid, phosphonic monoester and alkyne, including halides, ketone, and hydroxyl groups as substituents. Furthermore, we found that alkenylphosphonic monoesters proceed to give a wide range of phosphorus 2‐pyrones through oxidative annulation with alkynes. Mechanistic studies revealed that C? H bond metalation was the rate‐limiting step.     

REACTION BETWEEN 2-HYDROXY ESTERS OF HYPOPHOSPHOROUS ACID AND ALCOHOLS

Abstract

A study of the reaction between esters of hypophosphorous acid and alcohols is carried out. It has been established that the 2-hydroxy esters of hypophosphorous acid react with alcohols as a result of which phosphonous acids are formed. A possible scheme of this reaction is suggested.     

A novel method for the separation of bis(alpha-hydroxyalkyl)phosphinic acid diastereoisomers via formation of novel cyclic phosphinic acids

The reaction of aromatic and aliphatic aldehydes with hypophosphorus acid under microwave irradiation was examined. The reaction gave a mixture of a racemic pair of bis(alpha-hydroxyalkyl)phosphinic acids and acetal derivatives from the corresponding bis(alpha-hydroxyalkyl)phosphinic acids of meso-stereochemistry in good yield. The difference in solubility in organic solvents due to polarity allowed us to readily separate these compounds. This method constitutes an easy, rapid, and good-yielding preparation and separation of bis(alpha-hydroxyalkyl) phosphinic acid diastereoisomers from simple starting materials using microwave irradiation.     

Kinetics and mechanism of oxidation of phosphorus oxyacids by pyridinium hydrobromide perbromide

Oxidation of three lower oxyacids of phosphorus, viz. phosphinic, phenylphosphinic and phosphorous acids by pyridinium hydrobromide perbromide (PHPB), is first-order with respect to both oxyacid and PHPB. There is no effect on addition of acylonitrile and pyridinium bromide. On oxidation, deuterated phosphinic and phosphorous acids exhibit substantial kinetic isotope effects. The effect of solvent composition on reaction rate indicates that the transition state is more polar than the reactants. Reaction rates were determined at different temperatures and the activation parameters calculated. Alternative mechanisms, involving the two tautomeric forms of the oxyacid, have been formulated and it has been concluded that the reaction proceeds through the pentacoordinated tautomer. Transfer of a hydride ion from the oxyacid to PHPB, in the rate-determining step, has been proposed.     

Microwave‐Assisted Functionalization of Phosphinic Acids: Amidations versus Esterifications

Both the reaction enthalpies and enthalpies of activation obtained by high‐level quantum chemical calculations were against the direct amidation of phosphinic acids under traditional thermal conditions. However, the amidations, not expected to proceed on the basis of the endothermicity and the significantly high enthalpies of activation, did take place under microwave (MW) conditions in 30–36% conversions. As a comparison, the direct esterifications of phosphinic acids that are thermoneutral and have higher enthalpies of activation were quite efficient under MW conditions. The outcome of the MW‐assisted amidation is the balance of two effects. The local overheating effect could overcome the barrier meant by the enthalpy of activation, but the endothermicity works against this. Comparison of the results of the syntheses and the energetics calculated for the esterification and amidation of phosphinic acids enabled us to draw more general conclusions on the scope and limitation of the use of MW irradiation in organic syntheses. The traditional amidation of phosphinic acids via the phosphinic chloride intermediate gave the products in much better yields. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:91–99, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21068     

Chiral Lewis base-assisted Brønsted acid (LBBA)-catalyzed enantioselective cyclization of 2-geranylphenols

Chiral Lewis base-assisted Br?nsted acids (Chiral LBBAs) have been designed as new organocatalysts for biomimetic enantioselective cyclization. A salt of a chiral phosphonous acid diester with FSO(3)H catalyzes the enantioselective cyclization of 2-geranylphenols to give the desired trans-fused cyclized products with high diastereo- and enantioselectivities (up to 98:2 dr and 93% ee).     

Orthosilicate-mediated esterification of monosubstituted phosphinic acids

Monosubstituted phosphinic acids are esterified with orthosilicates in excellent yields. Phosphinylidene-containing acids react selectively under these conditions, while disubstituted phosphinic acids and phosphonic acids remain unchanged. One-pot procedures are also described for the preparation of phosphinate esters from an alcohol. This novel method provides a convenient and general alternative to more commonly employed conditions such as diazomethane or carbodiimide.     

Synthesis of alkyl- and aryl(o-oxyphenoxymethyl) phosphinic acids

Conclusions Cleavage of 2-oxo-2-chloromethyl-1,3,2-benzodioxaphosphole by Grignard reagents produced pyrocatechol esters of alkyl- and aryl(chloromethyl)phosphinic acids, cyclization of which and subsequent hydrolysis lead to alkyl- and aryl(o-oxyphenoxymethyl)phosphinic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 943–946, April, 1989.     

Synthesis,Crystal Structure and Complexing Properties of Phosphinic Analogues of Glycylglycine

Abstract

The phosphinic dipeptides of the general formula H₂NCH₂CONHCH₂P(R)(O)(OH) where R?Me, Ph and t-Bu has been synthetized from the free phosphinic acids and N-hydroxnunimide esters of the N-protected glycine. The deprotected dipeptida were purified by combination of the column chromato graphy on strong and week cation exchange resins by elution with diluted aqueous ammonia (0.1–3%)     

Methylenverbindungen von Nichtmetallen. VI. Amide der Methan-bis(phosphonigsäure), -bis(phosphonsäure) und -bis(thiophosphonsäure)

Methylene Compounds of Non-Metals. VI. Amides of Methane-bis(phosphonous Acid), -bis(phosphonic Acid) and -bis(thiophosphonic Acid) Symmetrical- and asymmetrical-substituted amides of methane-bis(phosphonous acid), -bis(phosphonic acid) and -bis(thiophosphonic acid) have been obtained by stepwise aminolysis of the chlorides Cl₂(Z)PCH₂P(Z)Cl₂ ( 1 : Z = electron pair; 7 : Z = S; 13 : Z = O) and the fluoride F₂(S)PCH₂P(S)F₂ 19 with dimethylaminotrimethylsilane. Oxidation reactions of trivalent phosphonous amides with sulfur and dimethylsulfoxide have also been investigated.