Phosphino‐Phosphination Reactions: Frustrated Lewis Pair Reactivity of Phosphino‐Phosphonium Cations with Alkynes

Kim, Hyehwang; Qu, Zheng‐wang; Grimme, Stefan; Al‐Zuhaika, Nahil; Stephan, Douglas W.

doi:10.1002/anie.202312587

Cited by 5 publications

(3 citation statements)

References 87 publications

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“…Overall these reactions of 7 ‐ Ph suggest that phosphine adduct formation at the reactive phosphenium ligands in this system is not inevitable and may be reversible, which is encouraging in the context of allowing possible alkene reactivity with 7 ‐ R in the presence of substrate phosphine. Indeed, there is precedent for the reversible coordination of phosphines to metal‐coordinated phosphenium ions, [10e] and the lability of the P−P bond in free “phosphinophosphonium” cations [R 3 P‐PR’ 2 ] + is well established [35] . Further studies of these Mo‐bound adducts and their reactivity are currently in progress.…”

Section: Resultsmentioning

confidence: 99%

Exploring Electrophilic Hydrophosphination via Metal Phosphenium Intermediates

Belli,

Muir,

Dyck

et al. 2024

Chemistry A European J

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Two Mo(0) phosphenium complexes containing ancillary secondary phosphine ligands have been investigated with respect to their ability to participate in electrophilic addition at unsaturated substrates and subsequent P‐H hydride transfer to “quench” the resulting carbocations. These studies provide stoichiometric “proof of concept” for a proposed new metal‐catalyzed electrophilic hydrophosphination mechanism. The more strongly Lewis acidic phosphenium complex, [Mo(CO)4(PR2H)(PR2)]+ (R = Ph, Tolp), cleanly hydrophosphinates 1,1‐diphenylethylene, benzophenone, and ethylene, while other substrates react rapidly to give products resulting from competing electrophilic processes. A less Lewis acidic complex, [Mo(CO)3(PR2H)2(PR2)]+, generally reacts more slowly but participates in clean hydrophosphination of a wider range of unsaturated substrates, including styrene, indene, 1‐hexene, and cyclohexanone, in addition to 1,1‐diphenylethylene, benzophenone, and ethylene. Mechanistic studies are described, including stoichiometric control reactions and computational and kinetic analyses, which probe whether the observed P‐H addition actually does occur by the proposed electrophilic mechanism, and whether hydridic P‐H transfer in this system is intra‐ or intermolecular. Preliminary reactivity studies indicate challenges that must be addressed to exploit these promising results in catalysis.

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Section: Resultsmentioning

confidence: 99%

Exploring Electrophilic Hydrophosphination via Metal Phosphenium Intermediates

Belli,

Muir,

Dyck

et al. 2024

Chemistry A European J

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“…This was subsequently generalized 103 with the reactions of the phosphino–phosphenium cations of the form [ClR 2 PPAr 2 ] + (Scheme 38). The P–P bond in these species proved to be labile, allowing access to the constituent Lewis acidic and Lewis basic fragments permitting FLP additions to alkynes.…”

Section: Stoichiometric Reactivitymentioning

confidence: 99%

Frustrated Lewis pair chemistry of alkynes

Guo,

Yan,

Stephan

2024

Org. Chem. Front.

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“…20 This prompted us to exploit PPCs in FLP additions to alkynes, affording a new route to dissymetrically substituted diphosphines. 21 In this paper, we probe the reactivity of PPCs with diazo-compounds, demonstrating that they behave as FLPs to effect addition or cleavage of NN double bonds.…”

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confidence: 99%