Spezifische photochemische Dehydrokupplung N‐heterocyclischer Phosphane und ihre Anwendung in der photokatalytischen Erzeugung von H<sub>2</sub>

Puntigam, Oliver; Könczöl, László; Nyulászi, László; Gudat, Dietrich

doi:10.1002/ange.201504504

Cited by 3 publications

(2 citation statements)

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“…Having previously reported that bi(diazaphospholidines) and bi(diazaphospholenes) are also accessible by photolysis driven dehydrocoupling of secondary phosphine precursors, [ 17 ] we wanted to explore the feasibility of this route for the preparation of { 7 } 2 . The secondary phosphine (Me 2 Si( t Bu)N) 2 PH ( 10 ) was readily prepared by LiBEt 3 H reduction of 8 and identified by its NMR spectroscopic data.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Thermally and Light Driven Cleavage of an N‐Heterocyclic Diphosphine with Inorganic Backbone

Blum

Feil

Nieger

et al. 2020

Zeitschrift anorg allge chemie

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A diphosphine with an unsupported PP bond connecting two carbon‐free “inorganic” 1,3,2,4,5‐diazaphosphadisilolidine rings was prepared by reductive coupling of a P‐chloro‐substituted monocyclic precursor molecule. VT‐EPR studies revealed that the diphosphine exists in solution, like other compounds of this kind, in dynamic equilibrium with the corresponding phosphinyl radicals. Determination of the radical concentration from the EPR spectra permitted to calculate thermochemical parameters for the homolytic PP bond fission. The results disclose that both the enthalpy and entropy of dissociation are higher than in topologically related bi(diazaphospholidines). The impact of the entropy term allows explaining that, regardless of the presence of an energetically rather stable PP bond, the onset of dissociation is observable even at ambient temperature. Irradiation experiments showed that radical formation cannot only be induced thermally, but also by photolysis.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Thermally and Light Driven Cleavage of an N‐Heterocyclic Diphosphine with Inorganic Backbone

Blum

Feil

Nieger

et al. 2020

Zeitschrift anorg allge chemie

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“…This was reported by Gudat using UV light. [27] The resulting (DAP) 2 species, described as a weakly σ-bonded dimer, would dissociate in…”

Section: Methodsmentioning

confidence: 99%

1,3,2‐Diazaphospholene‐Catalyzed Reductive Cyclizations of Organohalides**

2022

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1,3,2‐diazaphospholenes hydrides (DAP‐Hs) are highly nucleophilic organic hydrides serving as main‐group catalysts for a range of attractive transformations. DAP hydrides can act as stoichiometric hydrogen atom transfer agents in radical reactions. Herein, we report a DAP‐catalyzed reductive radical cyclization of a broad range of aryl and alkyl halides under mild conditions. The pivotal DAP catalyst turnover was achieved by a DBU‐assisted σ‐bond metathesis between the formed DAP halide and HBpin, which rapidly regenerates DAP‐H. The transformation is significantly accelerated by irradiation with visible light. Mechanistic investigations indicate that visible light irradiation leads to the formation of DAP dimers, which are in equilibrium with DAP radicals and accelerate the cyclization. The direct use of (DAP)2 enabled a catalytic protocol in the absence of light.

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Diazaphospholene‐Catalyzed Radical Reactions from Aryl Halides**

et al. 2022

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Diazaphospholenes are widely used as hydride transfer catalysts, however their use in radical reactions is a recently emerging area. Here, we show prior stoichiometric radical cyclizations of aryl iodides mediated by diazaphospholene hydrides are made catalytic by the combination of phenylsilane and alkali metal salts to regenerate the diazaphospholene hydride. The scope was expanded to include aryl bromides, which benefit from visible light irradiation. Twenty one substrates underwent cyclization, including a dearomative cyclization. Extension to six intermolecular radical hydroarylations with arenes, thiophenes, and a pyridine was also accomplished.

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Spezifische photochemische Dehydrokupplung N‐heterocyclischer Phosphane und ihre Anwendung in der photokatalytischen Erzeugung von H₂

Cited by 3 publications

References 30 publications

Synthesis and Thermally and Light Driven Cleavage of an N‐Heterocyclic Diphosphine with Inorganic Backbone

Synthesis and Thermally and Light Driven Cleavage of an N‐Heterocyclic Diphosphine with Inorganic Backbone

1,3,2‐Diazaphospholene‐Catalyzed Reductive Cyclizations of Organohalides**

Diazaphospholene‐Catalyzed Radical Reactions from Aryl Halides**

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Spezifische photochemische Dehydrokupplung N‐heterocyclischer Phosphane und ihre Anwendung in der photokatalytischen Erzeugung von H2

Cited by 3 publications

References 30 publications

Synthesis and Thermally and Light Driven Cleavage of an N‐Heterocyclic Diphosphine with Inorganic Backbone

Synthesis and Thermally and Light Driven Cleavage of an N‐Heterocyclic Diphosphine with Inorganic Backbone

1,3,2‐Diazaphospholene‐Catalyzed Reductive Cyclizations of Organohalides**

Diazaphospholene‐Catalyzed Radical Reactions from Aryl Halides**

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Spezifische photochemische Dehydrokupplung N‐heterocyclischer Phosphane und ihre Anwendung in der photokatalytischen Erzeugung von H₂