35Cl NQR spectra and molecular structure of cyclic chlorophosphoranes

The structure of chlorine-containing cyclic pentacoordinated phosphorus compounds has been studied by³⁵Cl NQR. The distortion of molecular geometry from trigonal bipyramid to tetragonal pyramid in going from monocyclic phosphoranes to spiro phosphoranes and the corresponding changes in the NQR spectrum are discussed.Perm State University. Institute of Organic Chemistry, Ukrainian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 3, pp. 75–79, May–June 1993.Translated by L. Smolina     

Chemistry of pentacoordinated anti-apicophilic phosphorus compounds

Since the synthesis of the first pentacoordinated organophosphorus compound, Ph₅P, by Wittig, the chemistry of pentacoordinated phosphorus compounds has been extensively expanded. Pentacoordinated phosphorus compounds usually take a trigonal bipyramidal structure with two distinctive sites; apical and equatorial positions. In the trigonal bipyramidal structure, electronegative and small substituents prefer the apical positions. Such properties are widely recognized as the apicophilicity rule. However, several examples breaking the apicophilicity rule have been reported in the past few decades and novel properties and reactivities of these new classes of compounds have been found. In this review, the synthesis of novel pentacoordinated phosphoranes with anti-apicophilic arrangement will be introduced, as well as their structures, spectroscopic properties, and reactivities.     

Ferrocene as Substituent in Organophosphorus Chemistry

Abstract

Synthesis and spectroscopic properties of ferrocenyl phosphanes and phosphoranes in low coordination are presented and discussed.     

PHOSPHORANES PAR FERMETURE TRANS ANNULAIRE IV. Quelques Exemples de Phosphoranes Bicycliques Chiraux

Abstract

Nous avons synthétisé sept phosphoranes bicycliques nouveaux 1–7 comportant un atome de phosphore pentacoordiné chiral. 5 et 6 possèdent en outre un atome de carbone chiral et 7 deux atomes de carbone chiraux. Une étude comparative des paramètres RMN du groupement P–H nous a permis de proposer une configuration de l'atome de phosphore de ces trois composés.

Seven new bicyclic phosphoranes 1–7 bearing a chiral pentaco-ordinated phosphorus atom are described. 5 and 6 possess a chiral carbon atom and 7 two chiral carbon atoms. A configuration of phosphorus atom of these three compounds is proposed based on a comparative study of the P–H NMR parameters.     

Bis(Pentamethylcyclopentadienyl)-Substituted Phosphanes and Phosphoranes

Abstract

The synthesis and crystal structures of a series of phosphanes and phosphoranes will be reported     

Photolysis of Phosphoniums and Phosphoranes Azides

Abstract

First evidence for a Curtius type rearrangement involving a pentacoordinated atom and charged species are described     

Intramolecular Cyclization of Hydridophos-Phorane Containing Unsaturated Bond

The tricyclic phosphoranes 4 and 5 were prepared by reaction of bicyclic phosphite 1 with unsaturated alcohols     

Concerning the Formation,Hydrolysis and Thermolysis of Acyclic Phosphoranes

Abstract

Kinetic data on the formation, hydrolysis and thermolysis of acyclic phosphoranes is reported and the mechanism of each reaction is discussed.     

PENTACOORDINATE SPIROCYCLIC DERIVATIVES OF THE 2H-1,2,3-DIAZAPHOSPHOLE SYSTEM

Abstract

Stable spirocyclic phosphoranes 2 have been prepared stereospecifically in high yields (90–95%) by reaction of o-azidophenol with cis and trans-diazaphosphole derivatives 1. Slow isomerization of pure diastereoisomer 2 was observed in acidic conditions.     

Reactivity of Conjugate Bases of Hydridophosphoranes. Synthesis of New Phosphoranes Involving P-P Bonds

Abstract

Hydridophosphoranes 1, 2 react, in presence of triethylamine, with phenyldichlorophosphine, diphenylchlorophosphine and the chlorophosphorane 3 giving unusual phosphoranes bearing P-P bonds. These last have been isolated and their structure has been determined by NMR spectroscopy.     

Synthesis of Hexa- and Pentacoordinated Phosphorus Compounds from White Phosphorus

Abstract

A new method is developed for the synthesis of phosphoranes (IIIa-d) and phosphorates (IVa-d) starting from substituted o-benzoquinones(Ia-d), catechols(IIa-d) and white phosphorus.     

Reactions of Tris(Perfluoroalkyl)Difluorophosphoranes and Their Derivatives with Nucleophilic Reagents

Abstract

This paper is concerned with the reactions of (R_f)₃PF₂ and (R_f)₃PO with N-, 0-, C-nucleophiles and fluoride ion. Either the replacement of one or two perfluoroalkyl radicals by different functional groups or the addition of reagent to electrophilic phosphorus occurs. These phosphinic oxides and phosphoranes readily add fluoride-ion with the expansion of phosphorus coordination: the former produces phosphoranes OP a new type (R_f)₃P(F)O_?Cs₊, while the latter stable substituted fluorophosphates of general formula M ₊[(R_f)₃ PF₃]_?. Based on these salts it was possible to synthesize aryldiazonium tris(perfluoroalkyl)trifluorophosphates, whose thermal decomposition leads to the formation of substituted fluorobenzenes with high yields. The reaction is a convenient modification of the Shieman methd. The approaches of the synthesis of phosphoranes containing simultaneously both perfluoroalkyl groups and nonfluorin-ated radicals are developed due to the reactions of tris-(perf luoroalkyl)dif luorophosphoranes with the lithium-organic compounds. The replacement of either fluorine atom or perfluoroalkyl radical by the nonfluorinated group depends on the lithium reagent nature:     

Organo-nonmetallic chemistry: Pentacoordinate,ten-electron (10-X-5) compounds of silicon,phosphorus and sulfur

Abstract

We have shown that ligands to nonmetals can be designed to stabilize five-coordinate species, relative to four- or six-coordinate ones. Nondissociative permutational isomerization of identically substituted hypervalent 10-Si-5 siliconate anions and neutral 10-P-5 phosphoranes is faster for the isoelectronic isostructural silicon species. Nucleophile mediated stereochemical inversion in silanes which are substituted by ligands which stabilize trigonal bipyramidal species is shown to proceed by pseudorotation of an intermediate 10-Si-5 species.     

The Effect of Very Bulky Groups on the Equilibrium of Penta- and Hexacoordinated Phosphoranes 1

The synthesis of dithio-diphenol 4 and sulfonyl-diphenol 5, both with very bulky groups, provided starting materials for reaction sequences that led to the formation of the very stable hexacoordinated phosphorane 2 and sensitive pentacoordinated phosphorane 3. Hexacoordination was established in 2 by an intramolecular donor interaction at the phosphorus center from an oxygen atom of the sulfonyl group present as part of the eight-membered ring. The solid state structures of 2 and 3 were established by X-ray analysis, as was that of phosphite 1 formed in the reaction sequence leading to 2. In solution, 2 has two forms existing in a dynamic equilibrium between a pentacoordinated and the more dominant hexacoordinated form as determined by ³¹P and ¹⁹F NMR spectroscopy. The high stability of 2 with respect to hydrolysis and alcoholysis reactions suggests that an associative process is responsible as the controlling reaction mechanism.     

Preparation and characterization of some stable acyclic oxyphosphoranes

A series of phosphoranes containing the hexafluoroisopropoxy group has been synthesized and characterized by ¹H, ¹⁹F, and ³¹P n.m.r., and by mass spectrometry. Some variable temperature n.m.r. studies are reported and the results are discussed in terms of possible ground state structures of the phosphoranes.     

The Effect of Trifluoroethoxy Groups on the Structures of Eight-Membered Ring-Containing Cyclic Phosphites 1

New phosphites 1–4 were synthesized from phosphorus trichloride and an appropriate diphenol followed by the addition of trifluoroethanol in the presence of triethylamine. These phosphites are to serve as precursors in the syntheses of biorelated hypervalent phosphoranes. ¹H, ¹⁹F, and ³¹P NMR spectra were recorded. X-ray analysis of 3 and 4 revealed that the sulfur-containing eight-membered ring was in a syn conformation that a allowed a sulfur donor interaction to the phosphorus atom, whereas for phosphite 2, the eight membered sulfonyl containing ring was in an anti conformation that did not allow a donor interaction to phosphorus from the oxygen atom of the sulfonyl group. Structural comparisons are made with related cyclic phosphites and phosphates having donor atoms in eight-membered rings.     

Pseudorotation and Conformational Transmission in Pentacoordinated Phosphorus Compounds

Abstract

This poster reviews our recent work on conformational transmission and pseudorotation in the pentacoordinated phosphorus (P^v) compounds 1a-d and 2a-d (1,2).     

The Structure of o-Hydroxyaryloxy-bis-(o-arylenedioxy)-phosphoranes and their Acid-Base Properties

Abstract

The crystalline phosphoranes have been obtained. IR-, UV- and NMR spectra of phosphoranes (Ia,b) and their interaction products with nitrogen bases have been investigated. It was determined that phosphoranes have structure (I) with pentacoordinate phosphorus and phenolic hydroxy group, while their products of interactions with nitrogen bases have the ionic structure (II) with hexacoordinate phosphorus (II). The X-ray difraction approves the structure (I) for phosphorane Ib.     

REACTIONS WITH PHOSPHACUMULENES: SYNTHESIS OF PYRAN DERIVATIVES FROM THE REACTION OF N-PHENYLIMINOKETENYLIDENE TRIPHENYL-PHOSPHORANE WITH α,β-UNSATURATED CARBONYL COMPOUNDS

Abstract

2-Benzylidene-1,3-indanedione (2), 4-benzylidene-1,2-diphenyl-3,5-pyrazolidenedione (4) and/or 5-benzylidenebarbituric acid (6) can be converted by reaction with N-phenyliminoketenylidene triphenylphosphorane (1) into pyransubstituted phosphoranes 3, 5 and 7. The structure of the new cyclic imino-phosphoranes 3, 5 and 7 was confirmed on the basis of elemental analysis and spectral studies. Moreover, when Wittig reaction was carried out on the pyran compound 7, using p-nitrobenzaldehyde, the new olefin 8 was isolated.     

Alkylation of Phosphorylmethylenetriphenylphosphoranes

Abstract

Direction of alkylation of phosphoranes (I) depends on the nature of the substituent Y and the alkylating agent. Unsubstituted phosphorane reacts with CH₃J yielding only the product of C-methylation (II), whereas the reaction with Me₂SO₄ proceeds at both ends of the OPC-triad, preferably yielding the O-alkylation product (IIIa, 80%).