Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane: is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane

Laurent Benisvy; Riccardo Wanke; Maxim L. Kuznetsov; M. Fátima C. Guedes da Silva; Armando J.L. Pombeiro

doi:10.1016/j.tet.2009.09.006

Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane: is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane

Laurent Benisvy, Riccardo Wanke, Maxim L. Kuznetsov, M. Fátima C. Guedes da Silva, Armando J.L. Pombeiro

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

15 Scopus citations

Abstract

Iodine oxidation, at -80 °C, of the carbanion in [{^-C(pz^Me2)₃}Li⁺(THF)] (1) (with pz^Me2=3,5-dimethylpyrazolyl) yields the C-centred radical in [{^{{radical dot}}C(pz^Me2)₃}Li(THF)]⁺ (1⁺), which, upon warming to room temperature, produces the unprecedented tetrakis(3,5-dimethylpyrazolyl)methane C(pz^Me2)₄ (3), the X-ray structure of which revealing intramolecular C-H⋯π interactions between each 5-Me group and an adjacent pyrazolyl ring. Oxidation of the radical by O₂ appears to lead to the novel ether (pz^Me2)₃C-O-C(pz^Me2)₃ (2).

Original language	English
Pages (from-to)	9218-9223
Number of pages	6
Journal	Tetrahedron
Volume	65
Issue number	45
DOIs	https://doi.org/10.1016/j.tet.2009.09.006
State	Published - 7 Nov 2009

Bibliographical note

Funding Information:
This work has been partially supported by the Foundation for Science and Technology (FCT), and its POCI 2010 programmes (FEDER funded), grant SFRH/BD/23187/2005 (R.W.), as well as by the Human Resources and Mobility Marie Curie Research Training Network (AQUACHEM project, CMTN-CT-2003-503864). L.B. thanks the EU for the provision of an ER fellowship within this project. M.L.K. is grateful to the FCT and IST for a research contract within the Ciência 2007 scientific programme.

Funding

This work has been partially supported by the Foundation for Science and Technology (FCT), and its POCI 2010 programmes (FEDER funded), grant SFRH/BD/23187/2005 (R.W.), as well as by the Human Resources and Mobility Marie Curie Research Training Network (AQUACHEM project, CMTN-CT-2003-503864). L.B. thanks the EU for the provision of an ER fellowship within this project. M.L.K. is grateful to the FCT and IST for a research contract within the Ciência 2007 scientific programme.

Funders	Funder number
Human Resources and Mobility Marie Curie Research Training Network	CMTN-CT-2003-503864
European Commission
Instituto Superior Técnico
European Regional Development Fund	SFRH/BD/23187/2005
Fundació Catalana de Trasplantament
Foundation for Science and Technology

Keywords

Carbanion
DFT calculations
Oxidation
Radical
Tris(pyrazolyl)methane

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10.1016/j.tet.2009.09.006

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Benisvy, L., Wanke, R., Kuznetsov, M. L., Guedes da Silva, M. F. C., & Pombeiro, A. J. L. (2009). Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane: is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane. Tetrahedron, 65(45), 9218-9223. https://doi.org/10.1016/j.tet.2009.09.006

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title = "Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane: is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane",

abstract = "Iodine oxidation, at -80 °C, of the carbanion in [\{-C(pzMe2)3\}Li+(THF)] (1) (with pzMe2=3,5-dimethylpyrazolyl) yields the C-centred radical in [\{\{radical dot\}C(pzMe2)3\}Li(THF)]+ (1+), which, upon warming to room temperature, produces the unprecedented tetrakis(3,5-dimethylpyrazolyl)methane C(pzMe2)4 (3), the X-ray structure of which revealing intramolecular C-H⋯π interactions between each 5-Me group and an adjacent pyrazolyl ring. Oxidation of the radical by O2 appears to lead to the novel ether (pzMe2)3C-O-C(pzMe2)3 (2).",

keywords = "Carbanion, DFT calculations, Oxidation, Radical, Tris(pyrazolyl)methane",

author = "Laurent Benisvy and Riccardo Wanke and Kuznetsov, \{Maxim L.\} and \{Guedes da Silva\}, \{M. F{\'a}tima C.\} and Pombeiro, \{Armando J.L.\}",

note = "Funding Information: This work has been partially supported by the Foundation for Science and Technology (FCT), and its POCI 2010 programmes (FEDER funded), grant SFRH/BD/23187/2005 (R.W.), as well as by the Human Resources and Mobility Marie Curie Research Training Network (AQUACHEM project, CMTN-CT-2003-503864). L.B. thanks the EU for the provision of an ER fellowship within this project. M.L.K. is grateful to the FCT and IST for a research contract within the Ci{\^e}ncia 2007 scientific programme. ",

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Benisvy, L, Wanke, R, Kuznetsov, ML, Guedes da Silva, MFC & Pombeiro, AJL 2009, 'Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane: is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane', Tetrahedron, vol. 65, no. 45, pp. 9218-9223. https://doi.org/10.1016/j.tet.2009.09.006

Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane: is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane. / Benisvy, Laurent; Wanke, Riccardo; Kuznetsov, Maxim L. et al.
In: Tetrahedron, Vol. 65, No. 45, 07.11.2009, p. 9218-9223.

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

TY - JOUR

T1 - Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane

T2 - is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane

AU - Benisvy, Laurent

AU - Wanke, Riccardo

AU - Kuznetsov, Maxim L.

AU - Guedes da Silva, M. Fátima C.

AU - Pombeiro, Armando J.L.

N1 - Funding Information: This work has been partially supported by the Foundation for Science and Technology (FCT), and its POCI 2010 programmes (FEDER funded), grant SFRH/BD/23187/2005 (R.W.), as well as by the Human Resources and Mobility Marie Curie Research Training Network (AQUACHEM project, CMTN-CT-2003-503864). L.B. thanks the EU for the provision of an ER fellowship within this project. M.L.K. is grateful to the FCT and IST for a research contract within the Ciência 2007 scientific programme.

PY - 2009/11/7

Y1 - 2009/11/7

N2 - Iodine oxidation, at -80 °C, of the carbanion in [{-C(pzMe2)3}Li+(THF)] (1) (with pzMe2=3,5-dimethylpyrazolyl) yields the C-centred radical in [{{radical dot}C(pzMe2)3}Li(THF)]+ (1+), which, upon warming to room temperature, produces the unprecedented tetrakis(3,5-dimethylpyrazolyl)methane C(pzMe2)4 (3), the X-ray structure of which revealing intramolecular C-H⋯π interactions between each 5-Me group and an adjacent pyrazolyl ring. Oxidation of the radical by O2 appears to lead to the novel ether (pzMe2)3C-O-C(pzMe2)3 (2).

AB - Iodine oxidation, at -80 °C, of the carbanion in [{-C(pzMe2)3}Li+(THF)] (1) (with pzMe2=3,5-dimethylpyrazolyl) yields the C-centred radical in [{{radical dot}C(pzMe2)3}Li(THF)]+ (1+), which, upon warming to room temperature, produces the unprecedented tetrakis(3,5-dimethylpyrazolyl)methane C(pzMe2)4 (3), the X-ray structure of which revealing intramolecular C-H⋯π interactions between each 5-Me group and an adjacent pyrazolyl ring. Oxidation of the radical by O2 appears to lead to the novel ether (pzMe2)3C-O-C(pzMe2)3 (2).

KW - Carbanion

KW - DFT calculations

KW - Oxidation

KW - Radical

KW - Tris(pyrazolyl)methane

UR - https://www.scopus.com/pages/publications/70349758235

U2 - 10.1016/j.tet.2009.09.006

DO - 10.1016/j.tet.2009.09.006

M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???

AN - SCOPUS:70349758235

SN - 0040-4020

VL - 65

SP - 9218

EP - 9223

JO - Tetrahedron

JF - Tetrahedron

IS - 45

ER -

Towards the functionalization of the methine carbon of a sterically hindered tris(pyrazolyl)methane: is a radical pathway envisageable? Synthesis and structure of tetrakis(3,5-dimethylpyrazolyl)methane

Abstract

Bibliographical note

Funding

Keywords

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