Phosphorus Heterocycles Research Articles

ChemInform Abstract: Mechanism of the Exchange Reaction of Halodiazirines with Nucleophiles Revisited. Synthesis of Neutral, Mono‐ or Dicationic 4‐16‐Membered Phosphorus Heterocycles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Reactive E = C(p‐p)π Systems. Part 41. 1,2,3‐Triphosphetenes, First Examples of a New Class of Phosphorus Heterocycles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Monocyclic and Fused 4-Imino(4-Oxo)-1,3,2-Diazaphospholanes and - Phosphorinanes. Synthesis and Some Properties

Abstract In contrast to the great variety of well known phosphorus heterocycles with exocyclic C=O double bond the number of ones containing exocyclic C=N bond is unusually modest. We elaborated the convenient method of preparation of various N,P,N-heterocycles with exocyclic C=N bond (1–4) from the readily available corresponding amino acid amidines and appropriated dichlorides or diamides of phosphorus (III) acids. Rings' 1–3 with P(III) are easily converted into (thio)phosphoryl derivatives, while the direct phosphorylation of amino amidines by RP(Y)Cl2 is unusually ineffective. Tricycles 4 - derivatives of 2-(2-amino pheny1)imidazoline - mainly exist in the more conjugated hydrophosphazo tautomeric form 4b (>90 %).

Gas-Phase Generated Phosphinidenes as a Route to Phosphorus Heterocycles - Formation of the First 3H-Phosphindole

Abstract Flash vacuum pyrolysis (FVP) over freshly resublimed magnesium on glass wool is a convenient and powerful dehalogenating procedure for a wide range of organic halides. We have now applied this system to the generation of phosphinidenes from the corresponding dichlorophosphines. As shown below, the production of phospholane from 1 and the interesting pyrophoric polymer 3 from 2 are readily explained by intramolecular insertion of the phosphinidenes. Under similar conditions 4 gives not only the expected phosphinidene insertion product, the phosphaindane 5, but also as a minor product, the 3-H-phosphaindene (“phosphindole”) 6 - the first example of a new heterocyclic system and the first 3-H-phosphole of any type.

Synthesis of homochiral dibenzo[b,f]phosphepin 5-oxides using a double ortho-lithiation strategy

Abstract Enantiomerically pure chiral seven membered phosphorus heterocycles — phosphepins — have been prepared by McMurry coupling, Sharpless dihydroxylation, ortho -lithiation and reaction with PhPCl 2 or PrPCl 2 . Studies of the ortho -lithiation and of hydrolysis of phosphepinium salts are included.

Direct Syntheses of 1-Phenylphosphetane and 1-Phenylphosphirane. Crystal and Molecular Structures of Neutral and Cationic Cyclotrimerization Precursor Complexes

Dilithium phenylphosphide reacts with 1,3-dichloropropane or 1,2-dichloroethane to give 1-phenylphosphetane (1) or 1-phenylphosphirane (2), respectively, both of which can be isolated by distillation in vacuo. The phosphetane rapidly polymerizes when neat but is stable in benzene wherefrom the polymer can be selectively and quantitatively separated from 1 by the addition of trans-dichlorobis(diethyl sulfide)palladium(II). Four-membered 1 has a remarkably low-field 31P NMR chemical shift (13.9 ppm), and 2, a remarkably high-field shift (−236 ppm). The crystal and molecular structures of the potential cyclotrimerization precursor complexes fac-[Mo(CO)3(1)3] (7), fac-[Mo(CO)3(2)3] (8), and [(η5-C5H5)Fe(2)3]PF6 (9) have been determined. Both molybdenum complexes have C3 symmetry in the solid state, and the iron complex has C1 symmetry. An interesting feature of the three structures is that the phenyl groups of the small phosphorus heterocycles in each case are arranged in groups of three syn or anti to the au...

1,2,3‐Triphosphetenes, First Examples of a New Class of Phosphorus Heterocycles

AbstractHitherto unknown 1,2,3‐triphosphetenes RCPPCF3PCF3 (3a–d) are formed as main products in reactions of phosphaalkynes RCP [R = iPr2N (1a), tBu (1b), Me2EtC (1c), 1‐methylcyclohexyl (1d)] with the cyclotetraphosphane (PCF3)4 (2). According to NMR results the CF3 groups in 3a–d have a trans disposition; an X‐ray diffraction study of 3a confirms this structure. The PP bond lengths in 3a are equal [2.201 (2) and 2.204 (2) Å] and correspond to single bonds. A considerable shortening is observed for the sp2‐C–N bond (1.336 Å) which, together with the elongation of the PC bond (1.746 Å), indicates effective π donation of the lone pair on nitrogen. Surprisingly, 3a can be prepared in quantitative yields by reaction of the PP ylide Me3PPCF3 (6) with 1 a (molar ratio: 2:1). In contrast, the corresponding reactions of 6 with the alkyl‐substituted phosphaalkynes 1b–d lead to the novel phosphorus ylides Me3PC(R)PPCF3PCF3PCF3 [R = tBu (10a), Me2EtC (10b), 1‐methylcyclohexyl (10c)] in good yields. In their molecular groundstate structures, determined by X‐ray diffraction, the lone pair on the phosphano P atom prefers the syn position with respect to the ylidic PC bond. An unusual lengthening of the sp2‐C–C bond [1.553 (4) (10a), 1.543 (6) (10b), 1.551 (4) Å (10c)] to values typical for sp3‐C/sp3‐C distances is observed.

λ5‐Phosphetes, Benzo‐λ5‐Phosphetes, Naphtho‐λ5‐Phosphetes: Four‐π‐, Eight‐π‐, and Twelve‐π‐Electron Systems

AbstractA number of possible strategies for the preparation of λ5‐phosphetes were tested as follows: cyclopropenium 6 was treated with the lithium salt of diphenylphosphine to give phosphinocyclopropene 7, but 7 did not undergo ring expansion upon photolysis or thermolysis. P‐chloro‐Ctrimethylsilyl‐substituted ylide 8b reacted with two equivalents of dimethyl acetylenedicarboxylate to afford phosphinine 13 via a transient λ5‐phosphete 12. Addition of aluminum trichloride to P‐halogenated ylides 17a–b led to dihydrophosphetium salts 19a–b, which, upon treatment with pyridine, isomerized into the 1, 2‐dihydrophosphet‐2‐ium salts 20a–b. Hydrolysis of derivatives 20a–b cleanly afforded phosphoniums 21 a–b, which reacted with NaN(SiMe3)2 to give rise to the corresponding λ5‐phosphetes 22a–b. The benzo‐λ5‐phosphete 22a underwent ring expansion reactions with dimethyl acetylenedicarboxylate and acetonitrile, leading to benzo‐λ5‐phosphinine and benzo‐1, 4λ5‐azaphosphinine in good yields. Derivative 22b was characterized by X‐ray crystal structure analysis. Ab initio SCF calculations, IGLO‐13C chemical shifts and Δχ for various benzannulated derivatives and phosphorus heterocycles are presented.

Mechanism of the Exchange Reaction of Halodiazirines with Nucleophiles Revisited. Synthesis of Neutral, Mono- or Dicationic 4−16-Membered Phosphorus Heterocycles

Trimethyl-, diphenylmethyl-, triphenyl-, diphenylthienyl-, and bis(dimethylamino)(isopropylthio)phosphine react with bromophenyldiazirine (1) giving cationic N,N‘-bis(phosphine) adducts 2a−c, 7, and 8 in 83−95% yields. Depending on the experimental conditions used, addition of 1,2-bis(diphenylphosphino)ethane to 1 leads to dicationic 14- and monocationic seven-membered heterocycles 3 (90% yield) and 4 (60% yield) or cationic N,N‘-bis(diphosphine) adduct 5 (86% yield); similarly, when diphenyl(isopropylthio)phosphine is used, competitive reactions occur, leading to cationic five-membered heterocycle 9 (34% yield) and/or N,N‘-Bis(diphosphine) adduct 10 (65% yield). 1,3-bis(diphenylphosphino)propane also reacts with 1, affording dicationic 16-membered heterocycle 6 (75% yield). Addition of bis(diisopropylamino)(trimethylstannyl)phosphine to 1 gives rise to a mixture of N-[(trimethylstannyl)imino]bis(diisopropylamino)bromophosphorane (11) (32%), 2,2-bis(diisopropylamino)-4-phenyl-1,3,2λ5-diazaphosphete (12) (26% yield), 1,3,5,2λ5-triazaphosphinine 13 (3% yield), benzonitrile (35%), and bromotrimethylstannane (60%). The mechanisms involved in these reactions are studied.

Synthesis of New Bidentate Phosphine Ligands Containing Saturated Phosphorus Heterocycles

The synthesis of two ethylene-bridged bidentate phosphines is described. 1,2-Bis(1-phospholano)ethane ((C(4)H(8))PCH(2)CH(2)P(C(4)H(8))) was synthesized by the stepwise addition of 2,2-dioxo-1,3,2-dioxathiepane to H(2)PCH(2)CH(2)PH(2). 1,2-Bis(1-phosphorinano)ethane ((C(5)H(10))PCH(2)CH(2)P(C(5)H(10))) was synthesized by the novel photochemical addition of 1,4-pentadiene to H(2)PCH(2)CH(2)PH(2). These bis(phosphines) form two-to-one complexes of the form Fe(PP)(2)Cl(2) when added to iron(II) chloride.

Phosphorylated imidazo[1,2‐a]pyridines

AbstractThe reaction of phosphorus(III) halides with imidazo[1,2‐a]pyridines in the presence of bases leads to the formation of 3‐phosphorylated imidazo[1,2‐a]pyridines. The reaction proceeds in high yield and requires no catalysts.In the compounds obtained, in contrast to phosphorylated indolizines, the phosphorus–heterocycle bond is stable and not cleaved by dry hydrogen chloride, alcohols, or water.Imidazo[1,2‐a]pyridines with the phosphinic and phosphinous groups can be alkylated both at the phosphorus and at the nitrogen atom of the heterocycle, the alkylation direction being dependent on the strength of the alkylation reagent used. © 1995 John Wiley & Sons, Inc.

Synthesis of the P‐sulfide derivatives of 3‐phosphabicyclo[3.1.0]hexanes and 1,2‐dihydrophosphinines

AbstractSeveral 3‐phosphabicyclo[3.1.0]hexane 3‐oxides have been transformed into the corresponding sulfides by reaction with phosphorus pentasulfide. The 3‐phenyl derivative could also be prepared by deoxygenation of the oxide followed by reaction with elemental sulfur. Opening of the cyclopropane ring in phosphabicyclohexane sulfides afforded mixtures of 3‐ and 5‐methyl‐1,2‐dihydro‐phosphinine‐1‐sulfides. Because of better yields, preparation of these products by thionation of the dihydrophosphinine oxides is more appropriate. The new phosphorus heterocycles have been characterized by 31P, 13C, and 1H NMR and mass spectral data.

SYNTHESES, CHARACTERIZATION AND REACTIVITY OF DIBENZOBICYCLIC PHOSPHORANES 10-P-5

Abstract Compound 1 has been prepared by demetallation with PCl3 of bis[3,5-di-tert-butyl-1,2-quinone-1-(2-hydroxy-3,5-di-tert-butylphenyl)imine] zinc complex 14. Compound 1 has been shown to be an excellent precursor in the syntheses of phosphorus heterocycles. The characterization of a new family of compounds such as those derived from 5-aza-2,8-dioxa-1-phosphav-dibenzo-[c,f]bicyclo-[3.3.0]octadiene in which the phosphorus substituents are X = chlorine 1, methyl 2, methoxy 3, isopropylamine 4, n-butylamine 5, sec-butylamine 6, tert-butylamine 7, 2-aminopyrimidine 8, glycol 9, catechol 10, 3,5-di-tert-butylcatechol 11, o-aminophenol 12, and phenylenediamine 13 is reported. The phosphorane system 10-P-5 of compounds 1–13 has been characterized by 1H, 13C and 31P NMR, IR, and mass spectra. The structure of compound 4 was determined by X-ray diffraction. Phosphoranes 1–8 have an aromatic, planar tetracyclic structure, in which the phosphorus atom is a trigonal bipyramid with the oxygen atoms in axial positions. Compounds 9–13 have the diphenolamine ligand in a folded conformation with two oxygen atoms in equatorial and the nitrogen in axial position.

Transition Metal Chemistry of Main Group Hydrazides, VI. New Directed Synthetic Strategies to Functionalized Heterocyclic Phosphorus(III) Hydrazides. First Examples of Crystal and Molecular Structures of [RPN(Me)N(H)]2 (R = Et, Ph, and tBu)

AbstractThe reactions of methylhydrazine with RPC12 (R = Et, tBu, and Ph) produced the cyclic phosphorus (III) hydrazides (1,2,4,5,3,6‐tetrazadiphosphorinanes) [RPN(Me)N(H)2 (R = Et, 1; (Ph, 2; tBu, 3) in good yields. The 1H‐and 31P‐NMR spectroscopic analysis indicated that 1 exists in chair and boat conformations. However, it crystallizes in the chair conformation exclusively. The X‐ray crystallographic investigation of all the three cyclo‐phosphorus hydrazides 1–3 confirms the existence of these compounds in the chair conformations in the solid state. The reaction of Mo(CO)4‐(NHC5H10)2 with 1 and 2 gives the dinuclear Mo(0) complexes [{Mo(CO)4(NHC5H10)}2(μ‐[RPN(Me)N(H)]2}] (R = Et, 5; Ph, 6). Based on 1H‐ and 31P‐NMR spectroscopic data, a bridging dinuclear dimetallic formulation is proposed for 5 and 6. The IR spectra indicate that the carbonyls are disposed in cis‐geometry around the Mo(0) center.

An Efficient Synthesis of Fused Phosphorus Heterocyclic Compounds (I)

Abstract The alkyl phosphorchloridisocyanate reacts with 3-benzylthio-5-amino-1,2,4-triazole and 3-benzylthio-5-amino-pyrazole respectively in the presence of triethylamine to form a kind of fused phosphorus heterocycles 3 and the mechanism of cyclization is discussed.

ChemInform Abstract: Donor‐Stabilized Monometaphosphates as Starting Compounds for Phosphorus Heterocycles

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Donor-Stabilized Monometaphosphates as Starting Compounds for Phosphorus Heterocycles

Abstract The reaction of donor-stabilized metaphosphoric acid derivatives like py∗PX2Y or Py2∗P2S5 with proton-active nucleophiles leads presumably to the intermediary formation of the corresponding monometaphosphate species which react via cyclo- or polyaddition to cyclic, and linear oligomeric or polymeric phosphorus compounds.

ChemInform Abstract: Four‐ and Five‐Membered Phosphorus Heterocycles. Part 78. 2‐ Aminopyridiniomethylphosphonite: A Hydrogen‐Bonded Polymer from the Hydrolysis of 1,3,4‐Diazaphospholo(1,2‐a)pyridine.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Three-Membered Phosphorus Heterocycles by Phosphanediyl Transfer-Reactions

Abstract Reactions of the chloro(trimethylsilyl)phosphane iPr2NP(SiMe3)Cl with Cl-P=C(SiMe3)2, Et3CP=NtBu, P≡CN(SiMe3)iPr, tBuB≡NtBu, as well as an intramolecular reaction of Cl (Me3Si)P-P=C (SiMe3) 2 have been carried out. We obtained in every reaction the corresponding [2+11-cycloadducts with the iPr2NP-unit except the latter case, there we obtained a dimer of a 3H-diphosphirene. The products have been characterized by means of 31P and 13C-NMR, as well as single crystal X-ray crystallography.

Synthese, Struktur und Isomerisierung von Diazaphosphiridinoxiden

Synthesis, Structure, and Isomerization of Diazaphosphiridine OxidesHerrn Professor Joseph Grobe zum 60. Geburtstag gewidmet. The 1,2‐Bis(alkyl)iminophosphane, Et3C — P=N — tBu (1), reacts with nitroso compounds, RNO (R=tBu, Ph), to form the diazaphosphiridine oxides, Et3C — YYP(=O) — NtBu — NYYR, 4a, b. While 4a (R=tBu) is thermally stable, 4b (R=Ph) isomerizes with formation of the benzodiazaphosphole oxide Et3C — YYP(= O) — NH — C6H4 — NYYtBu (5). The corresponding phospholimine Et3C — YYP(=NtBu) — NH — C6H4 — NYYtBu (7) has been obtained from 1 and azobenzene. The three‐membered phosphorus heterocycle 4a has been characterized by X‐ray structure analysis, which reveales some remarkable features.