Tandem Mn–I Exchange and Homocoupling Processes Mediated by a Synergistically Operative Lithium Manganate

Marina Uzelac; Pasquale Mastropierro; Marco de Tullio; Ivana Borilovic; Màrius Tarrés; Alan R. Kennedy; Guillem Aromí; Eva Hevia

doi:10.1002/anie.202013153

Tandem Mn–I Exchange and Homocoupling Processes Mediated by a Synergistically Operative Lithium Manganate

Marina Uzelac, Pasquale Mastropierro, Marco de Tullio, Ivana Borilovic, Màrius Tarrés, Alan R. Kennedy, Guillem Aromí, Eva Hevia

Department of Chemistry

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

21 Citations (SciVal)

Abstract

Pairing lithium and manganese(II) to form lithium manganate [Li₂Mn(CH₂SiMe₃)₄] enables the efficient direct Mn–I exchange of aryliodides, affording transient (aryl)lithium manganate intermediates which in turn undergo spontaneous C−C homocoupling at room temperature to furnish symmetrical (bis)aryls in good yields under mild reaction conditions. The combination of EPR with X-ray crystallographic studies has revealed the mixed Li/Mn constitution of the organometallic intermediates involved in these reactions, including the homocoupling step which had previously been thought to occur via a single-metal Mn aryl species. These studies show Li and Mn working together in a synergistic manner to facilitate both the Mn–I exchange and the C−C bond-forming steps. Both steps are carefully synchronized, with the concomitant generation of the alkyliodide ICH₂SiMe₃ during the Mn–I exchange being essential to the aryl homocoupling process, wherein it serves as an in situ generated oxidant.

Original language	English
Pages (from-to)	3247-3253
Number of pages	7
Journal	Angewandte Chemie - International Edition
Volume	60
Issue number	6
Early online date	22 Oct 2020
DOIs	https://doi.org/10.1002/anie.202013153
Publication status	Published - 8 Feb 2021

Bibliographical note

Funding Information:
We thank Robert Mulvey (University of Strathclyde) and Martin Albrecht (University of Bern) for their helpful comments on this work and Wowa Stroek for his valuable assistance on the use of EPR. We are also grateful to the University of Bern, ERC Stg‐MixMetApps_279590, the SNF (188573) and Spanish MINECO (PGC2018‐098630‐B‐I00) for the generous sponsorship of this research. The X‐ray crystal structure determination service unit of the Department of Chemistry and Biochemistry of the University of Bern is acknowledged for measuring, solving, refining and summarizing the structure of compound . The Synergy diffractometer was partially funded by the SNF within the R'Equip programme (206021_177033). 5

Funding Information:
We thank Robert Mulvey (University of Strathclyde) and Martin Albrecht (University of Bern) for their helpful comments on this work and Wowa Stroek for his valuable assistance on the use of EPR. We are also grateful to the University of Bern, ERC Stg-MixMetApps_279590, the SNF (188573) and Spanish MINECO (PGC2018-098630-B-I00) for the generous sponsorship of this research. The X-ray crystal structure determination service unit of the Department of Chemistry and Biochemistry of the University of Bern is acknowledged for measuring, solving, refining and summarizing the structure of compound 5. The Synergy diffractometer was partially funded by the SNF within the R'Equip programme (206021_177033).

Publisher Copyright:
© 2020 Wiley-VCH GmbH

Keywords

cooperative effects
homocoupling
lithium
manganese
structure elucidation

ASJC Scopus subject areas

Catalysis
General Chemistry

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10.1002/anie.202013153

Cite this

@article{4e9525806f4c423fa9bc3cf98b2d059f,

title = "Tandem Mn–I Exchange and Homocoupling Processes Mediated by a Synergistically Operative Lithium Manganate",

abstract = "Pairing lithium and manganese(II) to form lithium manganate [Li2Mn(CH2SiMe3)4] enables the efficient direct Mn–I exchange of aryliodides, affording transient (aryl)lithium manganate intermediates which in turn undergo spontaneous C−C homocoupling at room temperature to furnish symmetrical (bis)aryls in good yields under mild reaction conditions. The combination of EPR with X-ray crystallographic studies has revealed the mixed Li/Mn constitution of the organometallic intermediates involved in these reactions, including the homocoupling step which had previously been thought to occur via a single-metal Mn aryl species. These studies show Li and Mn working together in a synergistic manner to facilitate both the Mn–I exchange and the C−C bond-forming steps. Both steps are carefully synchronized, with the concomitant generation of the alkyliodide ICH2SiMe3 during the Mn–I exchange being essential to the aryl homocoupling process, wherein it serves as an in situ generated oxidant.",

keywords = "cooperative effects, homocoupling, lithium, manganese, structure elucidation",

author = "Marina Uzelac and Pasquale Mastropierro and {de Tullio}, Marco and Ivana Borilovic and M{\`a}rius Tarr{\'e}s and Kennedy, {Alan R.} and Guillem Arom{\'i} and Eva Hevia",

note = "Funding Information: We thank Robert Mulvey (University of Strathclyde) and Martin Albrecht (University of Bern) for their helpful comments on this work and Wowa Stroek for his valuable assistance on the use of EPR. We are also grateful to the University of Bern, ERC Stg‐MixMetApps_279590, the SNF (188573) and Spanish MINECO (PGC2018‐098630‐B‐I00) for the generous sponsorship of this research. The X‐ray crystal structure determination service unit of the Department of Chemistry and Biochemistry of the University of Bern is acknowledged for measuring, solving, refining and summarizing the structure of compound . The Synergy diffractometer was partially funded by the SNF within the R'Equip programme (206021_177033). 5 Funding Information: We thank Robert Mulvey (University of Strathclyde) and Martin Albrecht (University of Bern) for their helpful comments on this work and Wowa Stroek for his valuable assistance on the use of EPR. We are also grateful to the University of Bern, ERC Stg-MixMetApps_279590, the SNF (188573) and Spanish MINECO (PGC2018-098630-B-I00) for the generous sponsorship of this research. The X-ray crystal structure determination service unit of the Department of Chemistry and Biochemistry of the University of Bern is acknowledged for measuring, solving, refining and summarizing the structure of compound 5. The Synergy diffractometer was partially funded by the SNF within the R'Equip programme (206021_177033). Publisher Copyright: {\textcopyright} 2020 Wiley-VCH GmbH",

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AU - Uzelac, Marina

AU - Mastropierro, Pasquale

AU - de Tullio, Marco

AU - Borilovic, Ivana

AU - Tarrés, Màrius

AU - Kennedy, Alan R.

AU - Aromí, Guillem

AU - Hevia, Eva

N1 - Funding Information: We thank Robert Mulvey (University of Strathclyde) and Martin Albrecht (University of Bern) for their helpful comments on this work and Wowa Stroek for his valuable assistance on the use of EPR. We are also grateful to the University of Bern, ERC Stg‐MixMetApps_279590, the SNF (188573) and Spanish MINECO (PGC2018‐098630‐B‐I00) for the generous sponsorship of this research. The X‐ray crystal structure determination service unit of the Department of Chemistry and Biochemistry of the University of Bern is acknowledged for measuring, solving, refining and summarizing the structure of compound . The Synergy diffractometer was partially funded by the SNF within the R'Equip programme (206021_177033). 5 Funding Information: We thank Robert Mulvey (University of Strathclyde) and Martin Albrecht (University of Bern) for their helpful comments on this work and Wowa Stroek for his valuable assistance on the use of EPR. We are also grateful to the University of Bern, ERC Stg-MixMetApps_279590, the SNF (188573) and Spanish MINECO (PGC2018-098630-B-I00) for the generous sponsorship of this research. The X-ray crystal structure determination service unit of the Department of Chemistry and Biochemistry of the University of Bern is acknowledged for measuring, solving, refining and summarizing the structure of compound 5. The Synergy diffractometer was partially funded by the SNF within the R'Equip programme (206021_177033). Publisher Copyright: © 2020 Wiley-VCH GmbH

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N2 - Pairing lithium and manganese(II) to form lithium manganate [Li2Mn(CH2SiMe3)4] enables the efficient direct Mn–I exchange of aryliodides, affording transient (aryl)lithium manganate intermediates which in turn undergo spontaneous C−C homocoupling at room temperature to furnish symmetrical (bis)aryls in good yields under mild reaction conditions. The combination of EPR with X-ray crystallographic studies has revealed the mixed Li/Mn constitution of the organometallic intermediates involved in these reactions, including the homocoupling step which had previously been thought to occur via a single-metal Mn aryl species. These studies show Li and Mn working together in a synergistic manner to facilitate both the Mn–I exchange and the C−C bond-forming steps. Both steps are carefully synchronized, with the concomitant generation of the alkyliodide ICH2SiMe3 during the Mn–I exchange being essential to the aryl homocoupling process, wherein it serves as an in situ generated oxidant.

AB - Pairing lithium and manganese(II) to form lithium manganate [Li2Mn(CH2SiMe3)4] enables the efficient direct Mn–I exchange of aryliodides, affording transient (aryl)lithium manganate intermediates which in turn undergo spontaneous C−C homocoupling at room temperature to furnish symmetrical (bis)aryls in good yields under mild reaction conditions. The combination of EPR with X-ray crystallographic studies has revealed the mixed Li/Mn constitution of the organometallic intermediates involved in these reactions, including the homocoupling step which had previously been thought to occur via a single-metal Mn aryl species. These studies show Li and Mn working together in a synergistic manner to facilitate both the Mn–I exchange and the C−C bond-forming steps. Both steps are carefully synchronized, with the concomitant generation of the alkyliodide ICH2SiMe3 during the Mn–I exchange being essential to the aryl homocoupling process, wherein it serves as an in situ generated oxidant.

KW - cooperative effects

KW - homocoupling

KW - lithium

KW - manganese

KW - structure elucidation

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Tandem Mn–I Exchange and Homocoupling Processes Mediated by a Synergistically Operative Lithium Manganate

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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