Reversible C−H Activation, Facile C−B/B−H Metathesis and Apparent Hydroboration Catalysis by a Dimethylxanthene-Based Frustrated Lewis Pair

Petra Vasko; Ili A. Zulkifly; M. Ángeles Fuentes; Zhenbo Mo; Jamie Hicks; Paul C.J. Kamer; Simon Aldridge

doi:10.1002/chem.201801871

Reversible C−H Activation, Facile C−B/B−H Metathesis and Apparent Hydroboration Catalysis by a Dimethylxanthene-Based Frustrated Lewis Pair

Petra Vasko^*, Ili A. Zulkifly, M. Ángeles Fuentes, Zhenbo Mo, Jamie Hicks, Paul C.J. Kamer, Simon Aldridge

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

33 Citations (Scopus)

Abstract

A dimethylxanthene-based phosphine/borane frustrated Lewis pair (FLP) is shown to effect reversible C−H activation, cleaving phenylacetylene, PhCCH, to give an equilibrium mixture of the free FLP and phosphonium acetylide in CD₂Cl₂ solution at room temperature. This system also reacts with B−H bonds although in a different fashion: reactions with HBpin and HBcat proceed via C−B/B−H metathesis, leading to replacement of the -B(C₆F₅)₂ Lewis acid component by -Bpin/-Bcat, and transfer of HB(C₆F₅)₂ to the phosphine Lewis base. This transformation underpins the ability of the FLP to catalyze the hydroboration of alkynes by HBpin: the active species is derived from the HB(C₆F₅)₂ fragment generated in this exchange process.

Original language	English
Pages (from-to)	10531-10540
Number of pages	10
Journal	Chemistry - A European Journal
Volume	24
Issue number	41
DOIs	https://doi.org/10.1002/chem.201801871
Publication status	Published - 20 Jul 2018
Externally published	Yes

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@article{918e8ec6365e401886b2f58f75b29432,

title = "Reversible C−H Activation, Facile C−B/B−H Metathesis and Apparent Hydroboration Catalysis by a Dimethylxanthene-Based Frustrated Lewis Pair",

abstract = "A dimethylxanthene-based phosphine/borane frustrated Lewis pair (FLP) is shown to effect reversible C−H activation, cleaving phenylacetylene, PhCCH, to give an equilibrium mixture of the free FLP and phosphonium acetylide in CD2Cl2 solution at room temperature. This system also reacts with B−H bonds although in a different fashion: reactions with HBpin and HBcat proceed via C−B/B−H metathesis, leading to replacement of the -B(C6F5)2 Lewis acid component by -Bpin/-Bcat, and transfer of HB(C6F5)2 to the phosphine Lewis base. This transformation underpins the ability of the FLP to catalyze the hydroboration of alkynes by HBpin: the active species is derived from the HB(C6F5)2 fragment generated in this exchange process.",

keywords = "boranes, frustrated Lewis pairs, hydroboration, metal-free catalysis, phosphines",

author = "Petra Vasko and Zulkifly, {Ili A.} and Fuentes, {M. {\'A}ngeles} and Zhenbo Mo and Jamie Hicks and Kamer, {Paul C.J.} and Simon Aldridge",

note = "Publisher Copyright: {\textcopyright} 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim",

year = "2018",

month = jul,

day = "20",

doi = "10.1002/chem.201801871",

language = "English",

volume = "24",

pages = "10531--10540",

journal = "Chemistry - A European Journal",

issn = "0947-6539",

publisher = "Wiley-VCH Verlag GmbH",

number = "41",

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T1 - Reversible C−H Activation, Facile C−B/B−H Metathesis and Apparent Hydroboration Catalysis by a Dimethylxanthene-Based Frustrated Lewis Pair

AU - Vasko, Petra

AU - Zulkifly, Ili A.

AU - Fuentes, M. Ángeles

AU - Mo, Zhenbo

AU - Hicks, Jamie

AU - Kamer, Paul C.J.

AU - Aldridge, Simon

PY - 2018/7/20

Y1 - 2018/7/20

N2 - A dimethylxanthene-based phosphine/borane frustrated Lewis pair (FLP) is shown to effect reversible C−H activation, cleaving phenylacetylene, PhCCH, to give an equilibrium mixture of the free FLP and phosphonium acetylide in CD2Cl2 solution at room temperature. This system also reacts with B−H bonds although in a different fashion: reactions with HBpin and HBcat proceed via C−B/B−H metathesis, leading to replacement of the -B(C6F5)2 Lewis acid component by -Bpin/-Bcat, and transfer of HB(C6F5)2 to the phosphine Lewis base. This transformation underpins the ability of the FLP to catalyze the hydroboration of alkynes by HBpin: the active species is derived from the HB(C6F5)2 fragment generated in this exchange process.

AB - A dimethylxanthene-based phosphine/borane frustrated Lewis pair (FLP) is shown to effect reversible C−H activation, cleaving phenylacetylene, PhCCH, to give an equilibrium mixture of the free FLP and phosphonium acetylide in CD2Cl2 solution at room temperature. This system also reacts with B−H bonds although in a different fashion: reactions with HBpin and HBcat proceed via C−B/B−H metathesis, leading to replacement of the -B(C6F5)2 Lewis acid component by -Bpin/-Bcat, and transfer of HB(C6F5)2 to the phosphine Lewis base. This transformation underpins the ability of the FLP to catalyze the hydroboration of alkynes by HBpin: the active species is derived from the HB(C6F5)2 fragment generated in this exchange process.

KW - boranes

KW - frustrated Lewis pairs

KW - hydroboration

KW - metal-free catalysis

KW - phosphines

UR - http://www.scopus.com/inward/record.url?scp=85050402368&partnerID=8YFLogxK

U2 - 10.1002/chem.201801871

DO - 10.1002/chem.201801871

M3 - Article

SN - 0947-6539

VL - 24

SP - 10531

EP - 10540

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 41

ER -

Reversible C−H Activation, Facile C−B/B−H Metathesis and Apparent Hydroboration Catalysis by a Dimethylxanthene-Based Frustrated Lewis Pair

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