Addition Of Phosphite Research Articles

The Stereochemical Behavior of Terephthalic Schiff Bases in Addition of Dialkyl or Diaryl Phosphites

Addition of dialkyl (or diaryl) phosphites to N-alkyl terephthalic Schiff bases led exclusively to a meso-form but addition to N-aryl terephthalic Schiff bases depended on the substituent of the aryl group. Semi-empirical calculations were involved to find the reason of this phenomenon.

Phosphonyl Radical Addition to Enol Ethers. The Stereoselective Synthesis of Cyclic Ethers.

AbstractFor Abstract see ChemInform Abstract in Full Text.

1-AMINO-1-ARYL- AND 1-AMINO-1-HETEROARYL-METHANEPHOSPHONIC ACIDS AND THEIR N-BENZHYDRYL–PROTECTED DIETHYL ESTERS: PREPARATION AND CHARACTERIZATION

n-Benzhydryl-protected diethyl[3.3pc] esters of 1-amino-1-aryl- (phenyl, cumyl, p-dimethylaminophenyl, piperonyl, 1′-naphthyl, 9′-anthryl, 1′-pyrenyl) and 1-amino-1-heteroaryl- (furyl, 2′-thienyl, 3′-thienyl, 2′-pyrrolyl)-methanephosphonic acids, prepared by the addition of diethyl phosphite to the corresponding benzhydryl imines, have been isolated, purified, and characterized. The presence of chiral α -carbon and prochiral phosphorus in these esters gives rise to complicated features in their NMR spectra, which are discussed. Hydrolysis of the crude 1-aryl compounds in situ gave modest yields of the corresponding aminophosphonic acids (except for 1′-pyrenyl). Of the 1-heteroaryl derivatives, only the 2′-thienyl compound gave the expected aminophosphonic acid; in other cases, alternative[-18pc] modes of decomposition may occur under hydrolytic conditions. NMR and mass spectral data are given for all products.

Phosphate or phosphite addition promotes the proteolytic turnover of phosphate-starvation inducible tomato purple acid phosphatase isozymes

Within 48 h of the addition of 2.5 mM phosphate (HPO 4 2−, Pi) or phosphite (H 2PO 3 −, Phi) to 8-day-old Pi-starved (−Pi) tomato suspension cells: (i) secreted and intracellular purple acid phosphatase (PAP) activities decreased by about 12- and 6-fold, respectively and (ii) immunoreactive PAP polypeptides either disappeared (secreted PAPs) or were substantially reduced (intracellular PAP). The degradation of both secreted PAP isozymes was correlated with the de novo synthesis of two extracellular serine proteases having M rs of 137 and 121 kDa. In vitro proteolysis of purified secreted tomato PAP isozymes occurred following their 24 h incubation with culture filtrate from Pi-resupplied cells. The results indicate that Pi or Phi addition to −Pi tomato cells induces serine proteases that degrade Pi-starvation inducible extracellular proteins.

Weak intramolecular interactions as controlling factors in the diastereoselective formation of 3-phosphinoxido- and 3-phosphono-1,2,3,6-tetrahydrophosphinine 1-oxides

A series of 3-phosphinoxido-and 3-phosphono-1,2,3,6-tetrahydrophosphinine oxides was synthesized by the diastereoselective addition of diphenylphosphine oxide and dialkyl phosphites to the α,β-double-bond of 1,2-dihydrophosphinine oxides. Further refunctionalizations led to a 3-P(O)(OH) 2 derivative and to a disulfide. The conformation of the products was evaluated using the B3LYP/6-31+G ∗//B3LYP/3-21G ∗ method, validated by calculation for a simple tetrahydrophosphinine oxide with a known stereostructure. The preferred conformers of the 3-P(X)Z 2-tetrahydrophosphinine derivatives were among the twist-boat forms containing the exocyclic P-function in the axial position due to three kinds of favorable intramolecular interactions. Only the 3-P(O)(OH) 2 derivative was found to adopt a half-chair conformation as a consequence of intramolecular H-bonding.

Phosphonyl radical addition to enol ethers. The stereoselective synthesis of cyclic ethers

Addition of diethyl phosphite or diethyl thiophosphite to enol ethers, in the presence of a radical initiator, results in the regioselective synthesis of organophosphonate or phosphonothioate derivatives, respectively, under mild conditions. This method can be applied to the stereoselective formation of substituted tetrahydrofurans and tetrahydropyrans, on cyclisation of vinyl ethers bearing unsaturated side chains.

Phosphonyl radical addition to enol ethers. The stereoselective synthesis of cyclic ethers

Graphic Addition of diethyl phosphite or diethyl thiophosphite to enol ethers, in the presence of a radical initiator, results in the regioselective synthesis of organophosphonate or phosphonothioate derivatives, respectively, under mild conditions. This method can be applied to the stereoselective formation of substituted tetrahydrofurans and tetrahydropyrans, on cyclisation of vinyl ethers bearing unsaturated side chains.

A novel phosphorus–carbon bond formation by ring opening with diethyl phosphite of oxazolines derived from serine

A new reaction of oxazolines derived from serine with diethyl phosphite leading to ring opening products with P–C bond formation is reported. This reaction, which proceeds under neutral conditions and without the use of any halogenated intermediate, results in a mixture of racemic α- and β-phosphono alanines in an approximate 1:2 ratio, with isolated yields up to 77%. The mechanism involves the rearrangement of the oxazoline into the corresponding α-benzamido acrylate, followed by addition of the diethyl phosphite to the double bond. Since no significant transesterification is observed, this method constitutes a simple route for α- and β-phosphono amino acids bearing suitable protecting groups.

Synthesis of New Constrained Tricyclic Amines and Tricyclic Aminophosphonates Containing the 2‐Azatricyclo[3.3.0.03,6]octane Skeleton

AbstractA short and easy method for the preparation of the 2‐azatricyclo[3.3.0.03,6]octane skeleton is described. The key step consists of an intramolecular ring closure of an endo‐oriented amino group and an exo‐oriented bromine atom. The amines were prepared through reduction of a suitable bicyclic imine. Nucleophilic addition of phosphite to the imines gave the corresponding aminophosphonates, which could be ring‐closed to the tricyclic aminophosphonates through an analogous pathway. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

First synthesis of 1,1 ′-ferrocene bis-aminophosphonic esters

The series of aminophosphonates bearing the 1,1 ′-bis-substituted ferrocenyl moiety was obtained by the addition of dialkyl phosphites to an azomethine bond of Schiff bases derived from 1,1 ′-ferrocene-bis-carboxaldehyde. This addition led to both diastereoisomeric forms demonstrating its behaviour to be contrary to the addition to terephthalic Schiff bases, which led exclusively to a meso-form.

Sulfinimine‐Mediated Asymmetric Synthesis of β‐Hydroxy α‐Amino Phosphonates.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of 5′‐Amino‐5′‐phosphonate Analogues of Pyrimidine Nucleoside Monophosphates.

AbstractFor Abstract see ChemInform Abstract in Full Text.

High catalytic activity of RhCl 3, 3H 2O in HC(OEt) 3 for the hydroformylation of alkenes: effect of P(OPh) 3 on the selectivity

A new catalytic system formed of RhCl 3, 3H 2O as a catalyst and triethyl orthoformate, HC(OEt) 3, as a solvent showed high catalytic activity in the reaction of hydroformylation of aryl, terminal and internal alkyl alkenes, and also cycloalkenes. The addition of the triphenyl phosphite, P(OPh) 3, increased the selectivity toward the branched aldehydes with aryl alkenes.

Sulfinimine-mediated asymmetric synthesis of beta-hydroxy alpha-amino phosphonates.

The addition of potassium dialkyl phosphites to enantiopure O-protected alpha-hydroxy sulfinimine pseudoenantiomers affords beta-hydroxy alpha-amino phosphonates in good yield and de. The reaction exhibits a strong match-mismatch effect.

A New and Expedient Diastereoselective Synthesis of α‐(Hydroxyamino)phosphonates and α‐Aminophosphonates by Silyl Triflate Promoted Diethyl Phosphite Addition to Chiral N‐Benzyl Nitrones.

An efficient methodology for the synthesis of α-aminophosphonates has been developed taking advantage of the tert-butyldimethylsilyl triflate activated addition of diethyl phosphite to N-benzyl nitrones derived from chiral α-alkoxy and α-(Boc-amino) aldehydes. The stereoselective carbon− phosphorus bond-forming reaction proceeded smoothly to give α-(hydroxyamino)phosphonate intermediates as the primary adducts, which were subsequently converted into the corresponding polyhydroxylated α-amino- and α,β-diaminophosphonates by conventional reductive processes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Synthesis of 5'-amino-5'-phosphonate analogues of pyrimidine nucleoside monophosphates.

The 5'-amino-5'-phosphono derivatives of cytidine, cytosine arabinoside (ara-C), and uridine have been prepared via the corresponding nucleoside aldehydes. Phosphite addition to imines derived from the nucleoside aldehydes and p-methoxybenzylamine was efficient, and use of this amine allowed cleavage of the products to the parent amino phosphonic acids. The phosphite additions proved to be diastereoselective, with the cytidine and uridine derivatives favoring the 5'S stereochemistry and the ara-C derivative favoring the 5'R isomer. The stereochemistry of one cytidine derivative was established by single-crystal diffraction analysis, and detailed comparisons of the (13)C NMR data allowed assignments of the other amino phosphonates.

Stereoselective synthesis, solution structure and metal complexes of (1 S,2 S)-2-amino-1-hydroxyalkylphosphonic acids

The highly stereoselective synthesis of (1 S,2 S)-2-amino-1-hydroxyalkylphosphonic acids was achieved by addition of dimethyl phosphite to N-protected aminoaldehydes. Relative configuration and solution conformations of (1 S,2 S)-2-amino-1-hydroxy-alkylphosphonic acids (in D 2O) and their dimethyl esters (in CDCl 3 and CD 3OD) were established by means of NMR basing on the dependence between observed values of coupling constants ( 3 J HH, 3 J PC, 3 J HP) and corresponding dihedral angles. Potentiometric and spectroscopic methods were used for the evaluation of the structure of the complexes of (1 S,2 S)-2-amino-1-hydroxy-alkylphosphonic acids with Zn(II) and Cu(II) ions in aqueous solutions.

A New and Expedient Diastereoselective Synthesis of α‐(Hydroxyamino)phosphonates and α‐Aminophosphonates by Silyl Triflate Promoted Diethyl Phosphite Addition to Chiral N‐Benzyl Nitrones

AbstractAn efficient methodology for the synthesis of α‐aminophosphonates has been developed taking advantage of the tert‐butyldimethylsilyl triflate activated addition of diethyl phosphite to N‐benzyl nitrones derived from chiral α‐alkoxy and α‐(Boc‐amino) aldehydes. The stereoselective carbon− phosphorus bond‐forming reaction proceeded smoothly to give α‐(hydroxyamino)phosphonate intermediates as the primary adducts, which were subsequently converted into the corresponding polyhydroxylated α‐amino‐ and α,β‐diaminophosphonates by conventional reductive processes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Rhodium catalyzed hydroformylation of β-pinene and camphene: effect of phosphorous ligands and reaction conditions on diastereoselectivity

The effect of phosphorus ligands on the rhodium catalyzed hydroformylation of β-pinene and camphene has been studied. In unmodified systems, β-pinene undergoes a fast isomerization to α-pinene. At longer reaction times and higher temperatures, the isomerization equilibrium is shifted resulting in the 80% chemoselectivity for β-pinene hydroformylation products (97% trans). The addition of various diphosphines, phosphines or phosphites improves the chemoselectivity and shifts the hydroformylation towards cis aldehyde 3a. Both the rate and diastereoselectivity of the hydroformylation of β-pinene are largely influenced by the basicity of auxiliary ligands, but surprisingly no correlation between their steric characteristics and the diastereoselectivity of the catalytic system has been revealed for the ligands with cone angles of 128–165°. The systems with more basic ligands show lower activities, higher diastereoselectivities and usually higher chemoselectivities in the β-pinene hydroformylation. Camphene gives linear aldehyde 6, with virtually 100% regio- and chemoselectivity in both modified and unmodified systems. The addition of phosphorus ligands favors the formation of endo isomer 6b: 6a/ 6b≈1/1.5, whereas the ratio is ca. 1/1 in unmodified systems. Neither steric nor electronic parameters of the ligands have been found to influence significantly the diastereoselectivity of the camphene hydroformylation.

Synthesis of 4-phosphono-β-lactams via phosphite addition to acyliminium salts

4-Aryl-4-phosphono-β-lactams are prepared by acylation of iminium salts with chloroacetyl chloride followed by phosphite addition and ring closure using sodium hydride as a base. Deacylation of the iminium salt is in competition with the desired addition of phosphites to acyliminium salts, which lowers the yield of the reaction.