Quantum-chemical investigation of thermal transformations of tris(hydroxymethyl)phosphine

In keeping with the calculations of thermodynamic characteristics of possible transformations of tris(hydroxymethyl)phosphine in the framework of DFT-approach using hybrid exchange-correlation functional B3LYP with the basis 6–311++G** the probability of transformation of tris(hydroxymethyl)phosphine at the temperature below 350 K into methylbis(hydroxymethyl)phosphine oxide is higher than the conversion into methyl(hydroxymethyl)phosphine oxide, and at the temperature over 350 K the trend is opposite. The probability of the formation of a heterocyclic dimer at the temperature over 300 K is somewhat lower and of bis(hydroxymethyl)phosphine in the temperature range 250–550 K is significantly lower.     

Quantum-chemical calculations of thermodynamic parameters of the synthesis of tris(hydroxymethyl)phosphine

Thermodynamic characteristics of the process of tris(hydroxymethyl)phosphine synthesis are calculated by the Hartree-Fock-Roothaan method in the basises LANL2DZ and 6–31G. From the calculated data degrees of accumulation are found of the target product that correlate with experimental data. This fact can be taken into account at the choice of conditions for producing tris(hydroxymethyl)phosphine.     

New Phosphorus Chemistry Leads to Unnatural Aminoacid Trimers

Unnatural or modified amino acids have become important biochemical vectors because of their potential utility in diagnostic or therapeutic medicine. Our ongoing research in hydroxymethyl phosphine chemistry has provided unique reaction pathways to produce unnatural aminoacid. The reaction of tris(hydroxymethyl)phosphine (THP) with chiral aminoacid L-alanine produced trimeric alanine in excellent yields. The X-ray crystal structure of 1 shows an unusual layered structure with water molecules sandwiched between the layers. Implications of this new chemistry in such emerging areas as chiral technology and drug discovery will be presented.     

Reaction of tris(hydroxymethyl)phosphine and cinnamaldehyde in methanol

Reaction of tris(hydroxymethyl)phosphine with excess cinnamaldehyde in CH₃OH or CD₃OD, followed using NMR, proceeds via several phosphorus-containing intermediates, multiple transformations of organic parts, and with the solvent H/D isotope effect on products. In both solvents, one CH₂OH group of tris(hydroxymethyl)phosphine is readily replaced by the cinnamaldehyde moiety to give the primary product, a 1,3-oxaphosphorinane derivative. Slower replacement of the second CH₂OH group leads to a mixture of aliphatic and heterocyclic phosphine intermediates in a ratio of ~4:1 in CH₃OH and ~1:1 in CD₃OD; both intermediates contain alcohol and aldehyde groups and convert rapidly into intra- and intermolecular hemiacetals. The hemiacetals of the aliphatic phosphine rearrange further into an unsymmetrical trialkylphosphine oxide, whereas the hemiacetals of the heterocyclic phosphine react with the third mole of cinnamaldehyde to replace the third CH₂OH group of tris(hydroxymethyl)phosphine. All intermediates and products are formed as mixtures of stereoisomers.     

Tautomerism in 1,3,2,5-dioxaborataphosphorinanes and their analogs

In solutions ammonium 2,2,5-triphenyl-4,6-di-R-1,3,2,5-dioxaborataphosphorinanes are characterized by ioncomplex tautomerism. The complex form dissociates reversibly to a secondary phosphine and an aldehyde. The reaction of tris(hydroxymethyl) phosphine with isobutyl diphenylborate in the presence of formaldehyde and a tertiary amine gave 5,5'-spirobi (2,2-diphenyl-1,3,2,5-dioxaborataphosphorinanes).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1133–1139, May, 1990.     

Synthesis of 1,3-diynes via palladium-catalyzed reaction of 1, 1-dibromo-1-alkenes

[reaction: see text] Both symmetric and unsymmetric 1,3-diynes were prepared from the palladium-catalyzed reaction of 1,1-dibromo-1-alkenes. The formation of symmetric 1,3-diynes 2 (homocoupling) was catalyzed by a weak ligand, tris(2-furyl)phosphine (TFP), and the addition of catalytic amount of CuI accelerated the reaction. The synthesis of unsymmetric 1,3-diynes 4 (the Sonogashira reaction) required a highly electron rich tris(4-methoxyphenyl)phosphine as the ligand, and CuI promotes the formation of byproduct 1,1-diynyl-1-alkenes 5.     

Tris(tetramethylguanidinyl)phosphine: The Simplest Non-ionic Phosphorus Superbase and Strongly Donating Phosphine Ligand

We report the synthesis and properties of the much sought-after tris(1,1,3,3-tetramethylguanidinyl) phosphine P(tmg)₃, a crystalline, superbasic phosphine accessible through a short and scalable procedure from the cheap and commercially available bulk chemicals 1,1,3,3-tetramethylguanidine, tris(dimethylamino)-phosphine and phosphorus trichloride. The new phosphine exhibits exceptional electron donor properties and readily forms transition metal complexes with gold(I), palladium(II) and rhodium(I) precursors. The formation of zwitterionic Lewis base adducts with carbon dioxide and sulfur dioxide was explored. In addition, the complete series of phosphine chalcogenides was prepared from the reaction of P(tmg)₃ with N₂O and the elemental chalcogens.     

Reactions of tris(2-pyridyl)phosphines and tris(2-pyridyl)phosphine oxides with some electrophiles

Treatment of tris(2-pyridyl)phosphine or tris(2-pyridyl)phosphine oxide with electrophiles such as chlorine, bromine, deuterium chloride, or benzenediazonium chloride gave unusual coupling products, i.e., 5-chloro-, 5-bromo-, 5-deuterio-, or 5-phenylazo-2,2′-bipyridyls, respectively, as a major coupling product in each case. This is considered to be the result of electrophilic substitution on a pyridyl ring in a pentacovalent phosphorane intermediate formed in each reaction. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 439–449, 1997     

Alpha-monodeuterated benzyl alcohols and phosphobetaines from reactions of aromatic aldehydes with a water/D2O-soluble phosphine

With the aim of learning more about the bleaching action of pulps by (hydroxymethyl)phosphines, we reacted several benzaldehydes, containing MeO, Me, OH, or halogen substituents, with tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P, in aqueous solution at 90 degrees C under argon. Effective reduction of the aldehydes to the corresponding benzyl alcohols with concomitant oxidation of the phosphine to the phosphine oxide takes place, the reaction proceeding via an initially formed phosphonium species. When the reactions are carried out in D2O, the benzyl alcohol product from 3,4-dimethoxybenzaldehyde contains one deuterium atom at the benzyl-carbon atom, consistent with the last step of the mechanism involving a carbanion intermediate. With syringaldehyde (3,5-dimethoxy-4-hydroxy-benzaldehyde), the reduction product (syringyl alcohol) is more reactive toward the phosphine than is the starting aldehyde, and a zwitterionic, phosphobetaine product is formed. In D2O, the zwitterion benzyl protons and protons of the hydroxypropyl-CH2 adjacent to the P atom undergo H/D exchange via presumed phosphorus ylide intermediates. Under the same aqueous reaction conditions, tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P (THPP), does not undergo redox reactions with aliphatic aldehydes but simply promotes a base-catalyzed self-condensation (aldol) reaction. THPP reduction of an aromatic ketone is sluggish, presumably because the carbonyl C-atom is less electrophilic than that present in an aromatic aldehyde.     

Isomere Tritolylphosphine und deren Derivate. UV-Spektren und Dipolmomente

The UV spectra of tris(2-methylphenyl)phosphine (I), tris(3-methylphenyl)phosphine (II), tris(4-methylphenyl)phosphine (III), and of their phosphine oxides, phosphine sulfides, and methyl phosphonium iodides are given. The dipole moments of I–III in benzene at 20° C were also determined. I absorbs at the longest wavelength and this result may be interpreted by a broadening of the angle on phosphorus in I. This results also from the measured dipole moment, assuming a constant phosphorus ring moment and neglecting other ortho-effects.     

Cyclopropanecarbaldehyde with two protected hydroxymethyl groups

3,5-Dioxabicyclo[5.1.0]octane-8-carbaldehyde was synthesized in three steps, including initial stereoselective exo-cyclopropanation of 1,3-dioxacyclohept-5-ene with ethyl diazoacetate. The subsequent phosphorylation according to Abramov and Kabachnik-Fields gave the corresponding α-hydroxy(acetoxy)- and α-aminocyclopropylmethylphosphonates with protected hydroxymethyl moieties at the three-membered ring.     

Darstellung und Eigenschaften von Tris(diphenylamino)-phosphin

Preparation and Properties of Tris (diphenylamino) Phosphine The synthesis and some properties of tris(diphenylamino)phosphine are described. Displacement of the chlorine atom is readily achieved by reaction of (Ph₂N)₂PCl with Ph₂NSime₃. Thus tris(diarylamino)phosphine (Ph₂N)₃P is obtained almost in quantitativ yield. The aminolysis reaction of PCl₃ or (Ph₂N)₂PCl with Ph₂NH gives also (Ph₂N)₃P. The properties and structure of the phosphine on basis of spectroscopical and X-ray investigations are discussed.     

Development of a series of P(CH(2)N=CHR)(3) and trisubstituted 1,3,5-Triaza-7-phosphaadamantane ligands

The synthesis and structure of a series of novel phosphine ligands derived from the condensation of P(CH2NH2) with aldehydes are described. Depending on the reaction conditions, either substituted tris(iminomethyl)phosphine, P(CH2N=CHR)3, or 1,3,5-triaza-7-phosphaadamantane structures substituted at the "lower rim", PTAR3, are obtained.     

Novel 1‐Aminomethylisatins: Peculiarities of the Synthesis and the Reaction with Tris(diethylamino)phosphine

The Mannich reaction of isatin with different primary and secondary amines and effect of the substituent in aromatic amines on the reaction pathway is studied. The efficient high‐yield synthesis of novel isoindigo derivatives by the mild deoxygenation reaction of the corresponding isatins with tris(diethylamino)phosphine is described.     

"Extracting" the Key Fragment in ETS-10 Crystallization and Its Application in AM-6 Assembly

The mechanism of crystallization of microporous titanosilicate ETS-10 was investigated by Raman spectroscopy combined with (29) Si magic-angle spinning (MAS) NMR spectroscopy, DFT calculations, and SEM imaging. The formation of three-membered ring species is shown to be the key step in the hydrothermal synthesis of ETS-10. They are formed by means of a complex process that involves the interaction of silicate species in the reaction mixture, which promotes the dissolution of TiO(2) particles. These insights into the mechanism of ETS-10 growth led to the successful development of a new synthesis route to the vanadosilicate AM-6 that involves the use of intermediates that contain three-membered ring species as an initiator.     

Furfuryl-containing tertiary phosphine oxides and polymers based on some of them

The syntheses of dimethyl(furfuryloxymethyl)phosphine oxide (DPO), methylbis(furfuryloxymethyl)phosphine oxide (MPO), tris(furfuryloxymethyl)phosphine oxide (TPO), dimethyl(tetrahydrofurfuryloxymethyl)phosphine oxide (DTPO), methyl-bis(tetrahydrofurfuryloxymethyl)phosphine oxide (MTPO) and tris(tetrahydrofurfuryloxymethyl)phosphine oxide (TTPO) from dimethyl(chloromethyl)phosphine oxide, methyl-bis(chloromethyl)phosphine oxide, tris(chloromethyl)phosphine oxide and the furfuryl and tetrahydrofurfuryl sodium alkoxides via the Williamson reaction are reported. Phosphorus-containing furan polymers with reduced flammability are prepared by polymerizing MPO and TPO using p-toluenesulphonic acid as catalyst. The oxygen indexes of these polymers, as determined by ASTM D-2863, are 35.1 and 33.1% O₂, respectively; for the phosphorus-free polymer from difurfurylidene acetone, it is 23.0% O₂. It is shown that DPO can be used as an efficient fire-retardant for reducing the flammability of a polymer from difurfurylidenacetone.     

Immobilization of palladium nanoparticles as a recyclable heterogeneous catalyst for the Suzuki–Miyaura coupling reaction

This work describes the synthesis of Pd nanoparticles that are stabilized on CaAl-layered double hydroxide functionalized with Tris (tris(hydroxymethyl)aminomethane). The synthesized catalyst is characterized by several different analyses and has been successfully applied to the Suzuki–Miyaura reaction.     

A Neutral Three-Membered 2π Aromatic Disilaborirane and the Unique Conversion into a Four-Membered BSi2N-Ring

We report the design, synthesis, structure, bonding, and reaction of a neutral 2π aromatic three-membered disilaborirane. The disilaborirane is synthesized by a facile one-pot reductive dehalogenation of amidinato-silylene chloride and dibromoarylborane with potassium graphite. Despite the tetravalent arrangement of atoms around silicon, the three-membered silicon-boron-silicon ring is aromatic, as evidenced by NMR spectroscopy, nucleus independent chemical shift calculations, first-principles electronic structure studies using density functional theory (DFT) and natural bond orbital (NBO) based bonding analysis. Trimethylsilylnitrene, generated in situ, inserts in the Si−Si bond of disilaborirane to obtain a four-membered heterocycle 1-aza-2,3-disila-4-boretidine derivative. Both the heterocycles are fully characterized by X-ray crystallography.     

Reactions of p-Hydroxyphenylphosphine and Functionally Substituted Bis(hydroxymethyl)phosphines with Heterocumulenes

Reactions of p-hydroxyphenylphosphine, bis(hydroxymethyl)(p-hydroxyphenyl)phosphine, and bis(hydroxymethyl)(5-allyl-2-ethoxybenzyl)phosphine with nitrogen-containing heterocumulenes were studied. The competitive reactivity of the phenol, phosphine, and hydroxymethyl groups in these reactions was examined.     

Synthesis of 2,2,3,3-tetracyanocyclopropyl ketones and their reactions with oxygen-centered nucleophiles

A procedure for the synthesis of 2,2,3,3-tetracyanocyclopropyl ketones has been developed on the basis of three-component Wideqvist reaction of dihydroxymethyl ketones, 2-bromomalononitrile, and malononitrile. The presence of five electron-withdrawing groups in the resulting cyclopropyl ketones determines high acidity of proton in the cyclopropane ring. Facile deprotonation by the action of bases promotes opening of the three-membered ring with formation of either 1,1,3,3-tetracyanopropenides or (in the presence of alcohols or oximes), [2-alkoxy(aminooxy)-5-amino-4-cyanofuran-3(2H)-ylidene]malononitriles. The reaction with acetone oxime was not accompanied by cleavage of the three-membered ring, and nucleophilic attack was directed at the cyano groups in the trans position with respect to the carbonyl group to give the corresponding (1R*,5S*,6R*)-4-amino-2,2-bis(prop-2-ylideneaminooxy)-3-azabicyclo[3.1.0]hex-3-ene-1,5-dicarbonitriles.