Alkaline Decomposition of Some Unsaturated Cyclic Phosphonium Compounds.

Bergesen, Knut; Bernbäck, Marie-Louise; Widemann, C.; Kulonen, E.; Brunvoll, J.; Bunnenberg, E.; Djerassi, Carl; Records, Ruth

doi:10.3891/acta.chem.scand.20-0899

Cited by 16 publications

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“…Simple phospholes readily form oxides (6,9,12,13,16a), sulfides (6,9,13,16a), selenides (13,16a),P-dibromides (13) and quaternary salts (10,13,22). Phosphole oxides are normally prepared by the treatment of phospholes with hydrogen peroxide (9,12,13,16a) but solutions of phospholes having aryl substituents on the ring carbon atom and alkyl substitutents (e.g.…”

Section: Reactions Of Simple Phosphole Derivativesmentioning

confidence: 99%

The chemistry of phosphole derivatives

Hughes

Srivanavit

1970

Journal of Heterocyclic Chem

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Synthetic approaches to, and the chemistry of, phospholes, benzophospholes and dibenzophospholes are reviewed and particular attention is paid to the possible aromatic character of the phosphole ring. Systems containing the 2H‐ and 3H‐phosph(V)ole nucleus are surveyed as are phosphole derivatives containing pentacovalent and six‐coordinate phosphorus. Stereochemical considerations in the more complex phosphole derivatives are discussed.

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Section: Reactions Of Simple Phosphole Derivativesmentioning

confidence: 99%

The chemistry of phosphole derivatives

Hughes

Srivanavit

1970

Journal of Heterocyclic Chem

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“…The best documented ring-opening reaction takes place upon hydrolysis of phospholium salts (Scheme 23.24) [72,73]. In the transient hydroxyphosphorane, the phosphole ring probably occupies a axial-equatorial position, leading to cleavage of the elongated axial PÀC bond.…”

Section: Ring Openings and Expansionsmentioning

confidence: 99%

Phosphorus Heterocycles

Mathey

2011

Modern Heterocyclic Chemistry

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Figure 23.1 The three isomers of the phosphole system (A-C) and the phospholide ion (D).2072j 23 Phosphorus Heterocycles shown with 1-alcoxyphospholes, which are relatively flat with a negligible delocalization [12]. Contrary to phospholes, the structure of phospholide ions reflects their high aromaticity. For example, the planar 2,3,4,5-tetramethylphospholide with Li(TMEDA) þ as the counterion displays the following parameters [13]: P-C, 1.715 A ; C¼C, 1.396 A ; CÀC, 1.424 A ;

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“…Consistent with the above mechanism, phosphonium salt hydrolyses are usually first‐order in phosphonium salt, second‐order in hydroxide, and therefore third‐order overall . Exceptional cases are known in which reactions show first‐order dependence on hydroxide concentration, for example, the hydrolysis reactions of para ‐nitrobenzyltriphenylphosphonium bromide, of methyltris(pentafluorophenyl)phosphonium fluorosulfonate, and of phospholium iodides …”

Section: Introductionmentioning

confidence: 99%

“…The alkaline hydrolysis of phosphonium salts is one of the prototypical reactions in phosphorus chemistry, having been reported on for the first time (to our knowledge) as early as 1857 . The reaction has been the subject of numerous mechanistic investigations over the course of many years . Phosphorane (P V ) species are the only observable intermediates in phosphonium salt and ylide hydrolysis and alcoholysis reactions (vide infra) .…”

Section: Introductionmentioning

confidence: 99%

The Mechanism of Phosphonium Ylide Alcoholysis and Hydrolysis: Concerted Addition of the O−H Bond Across the P=C Bond

Byrne

Gilheany

2016

Chemistry A European J

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The previous work on the hydrolysis and alcoholysis reactions of phosphonium ylides is summarized and reviewed in the context of their currently accepted mechanisms. Several experimental facts relating to ylide hydrolysis and to salt and ylide alcoholysis are shown to conflict with those mechanisms. In particular, we demonstrate that the pKa values of water and alcohols are too high in organic media to bring about protonation of ylide. Therefore, we propose concerted addition of the water or alcohol O-H bond across the ylide P=C bond. In support of this, we provide NMR spectroscopic evidence for equilibrium between ylide and aclohol that does not require the involvement of phosphonium hydroxide. We report the first P-alkoxyphosphorane to be characterised by NMR spectroscopy that does not undergo exchange on an NMR timescale. Two-dimensional NMR spectroscopic techniques have been applied to the characterisation to P-alkoxyphosphoranes for the first time.

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Alkaline Decomposition of Some Unsaturated Cyclic Phosphonium Compounds.

Cited by 16 publications

References 0 publications

The chemistry of phosphole derivatives

The chemistry of phosphole derivatives

Phosphorus Heterocycles

The Mechanism of Phosphonium Ylide Alcoholysis and Hydrolysis: Concerted Addition of the O−H Bond Across the P=C Bond

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