Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities

Michael A. Stevens; Fairuz H. Hashim; Eunice S.H. Gwee; Ekaterina I. Izgorodina; Robert E. Mulvey; Victoria L. Blair

doi:10.1002/chem.201803477

Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities

Michael A. Stevens, Fairuz H. Hashim, Eunice S.H. Gwee, Ekaterina I. Izgorodina, Robert E. Mulvey, Victoria L. Blair^*

^*Corresponding author for this work

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

8 Citations (Scopus)

Abstract

A series of dialkylphenylphosphines and their analogous aniline substrates have been metallated with the synergistic mixed-metal base [(TMEDA)Na(TMP)(CH₂SiMe₃)Mg(TMP)] 1. Different metallation regioselectivities for the substrates were observed, with predominately lateral or meta-magnesiated products isolated from solution. Three novel heterobimetallic complexes [(TMEDA)Na(TMP)(CH₂PCH₃Ph)Mg(TMP)] 2, [(TMEDA)Na(TMP)(m-C₆H₄PiPr₂)Mg(TMP)] 3 and [(TMEDA)Na(TMP)(m-C₆H₄NEt₂)Mg(TMP)] 4 and two homometallic complexes [{(TMEDA)Na(EtNC₆H₅)}₂] 5 and [(TMEDA)Na₂(TMP)(C₆H₅PEt)]₂ 6 derived from homometallic metallation have been crystallographically characterised. Complex 6 is an unprecedented sodium-amide, sodium-phosphide hybrid with a rare (NaNNaP)₂ ladder motif. These products reveal contrasting heterobimetallic deprotonation with homometallic induced ethene elimination reactivity. Solution studies of metallation mixtures and electrophilic iodine quenching reactions confirmed the metallation sites. In an attempt to rationalise the regioselectivity of the magnesiation reactions the C−H acidities of the six substrates were determined in THF solution using DFT calculations employing the M06-2X functional and cc-pVTZ Dunning's basis set.

Original language	English
Pages (from-to)	15669-15677
Number of pages	9
Journal	Chemistry - A European Journal
Volume	24
Issue number	58
DOIs	https://doi.org/10.1002/chem.201803477
Publication status	Published - 17 Oct 2018
Externally published	Yes

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Stevens, M. A., Hashim, F. H., Gwee, E. S. H., Izgorodina, E. I., Mulvey, R. E., & Blair, V. L. (2018). Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities. Chemistry - A European Journal, 24(58), 15669-15677. https://doi.org/10.1002/chem.201803477

@article{a7710b8f7eb248bd9179a27d82953bb9,

title = "Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities",

abstract = "A series of dialkylphenylphosphines and their analogous aniline substrates have been metallated with the synergistic mixed-metal base [(TMEDA)Na(TMP)(CH2SiMe3)Mg(TMP)] 1. Different metallation regioselectivities for the substrates were observed, with predominately lateral or meta-magnesiated products isolated from solution. Three novel heterobimetallic complexes [(TMEDA)Na(TMP)(CH2PCH3Ph)Mg(TMP)] 2, [(TMEDA)Na(TMP)(m-C6H4PiPr2)Mg(TMP)] 3 and [(TMEDA)Na(TMP)(m-C6H4NEt2)Mg(TMP)] 4 and two homometallic complexes [{(TMEDA)Na(EtNC6H5)}2] 5 and [(TMEDA)Na2(TMP)(C6H5PEt)]2 6 derived from homometallic metallation have been crystallographically characterised. Complex 6 is an unprecedented sodium-amide, sodium-phosphide hybrid with a rare (NaNNaP)2 ladder motif. These products reveal contrasting heterobimetallic deprotonation with homometallic induced ethene elimination reactivity. Solution studies of metallation mixtures and electrophilic iodine quenching reactions confirmed the metallation sites. In an attempt to rationalise the regioselectivity of the magnesiation reactions the C−H acidities of the six substrates were determined in THF solution using DFT calculations employing the M06-2X functional and cc-pVTZ Dunning's basis set.",

keywords = "anilines, dialkylphenyphosphines, metallation, regioselectivity, synergistic effect",

author = "Stevens, {Michael A.} and Hashim, {Fairuz H.} and Gwee, {Eunice S.H.} and Izgorodina, {Ekaterina I.} and Mulvey, {Robert E.} and Blair, {Victoria L.}",

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

year = "2018",

month = oct,

day = "17",

doi = "10.1002/chem.201803477",

language = "English",

volume = "24",

pages = "15669--15677",

journal = "Chemistry - A European Journal",

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publisher = "Wiley-VCH Verlag",

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Stevens, MA, Hashim, FH, Gwee, ESH, Izgorodina, EI, Mulvey, RE & Blair, VL 2018, 'Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities', Chemistry - A European Journal, vol. 24, no. 58, pp. 15669-15677. https://doi.org/10.1002/chem.201803477

Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities. / Stevens, Michael A.; Hashim, Fairuz H.; Gwee, Eunice S.H. et al.
In: Chemistry - A European Journal, Vol. 24, No. 58, 17.10.2018, p. 15669-15677.

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

TY - JOUR

T1 - Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines

T2 - Lateral versus Ring Selectivities

AU - Stevens, Michael A.

AU - Hashim, Fairuz H.

AU - Gwee, Eunice S.H.

AU - Izgorodina, Ekaterina I.

AU - Mulvey, Robert E.

AU - Blair, Victoria L.

PY - 2018/10/17

Y1 - 2018/10/17

N2 - A series of dialkylphenylphosphines and their analogous aniline substrates have been metallated with the synergistic mixed-metal base [(TMEDA)Na(TMP)(CH2SiMe3)Mg(TMP)] 1. Different metallation regioselectivities for the substrates were observed, with predominately lateral or meta-magnesiated products isolated from solution. Three novel heterobimetallic complexes [(TMEDA)Na(TMP)(CH2PCH3Ph)Mg(TMP)] 2, [(TMEDA)Na(TMP)(m-C6H4PiPr2)Mg(TMP)] 3 and [(TMEDA)Na(TMP)(m-C6H4NEt2)Mg(TMP)] 4 and two homometallic complexes [{(TMEDA)Na(EtNC6H5)}2] 5 and [(TMEDA)Na2(TMP)(C6H5PEt)]2 6 derived from homometallic metallation have been crystallographically characterised. Complex 6 is an unprecedented sodium-amide, sodium-phosphide hybrid with a rare (NaNNaP)2 ladder motif. These products reveal contrasting heterobimetallic deprotonation with homometallic induced ethene elimination reactivity. Solution studies of metallation mixtures and electrophilic iodine quenching reactions confirmed the metallation sites. In an attempt to rationalise the regioselectivity of the magnesiation reactions the C−H acidities of the six substrates were determined in THF solution using DFT calculations employing the M06-2X functional and cc-pVTZ Dunning's basis set.

AB - A series of dialkylphenylphosphines and their analogous aniline substrates have been metallated with the synergistic mixed-metal base [(TMEDA)Na(TMP)(CH2SiMe3)Mg(TMP)] 1. Different metallation regioselectivities for the substrates were observed, with predominately lateral or meta-magnesiated products isolated from solution. Three novel heterobimetallic complexes [(TMEDA)Na(TMP)(CH2PCH3Ph)Mg(TMP)] 2, [(TMEDA)Na(TMP)(m-C6H4PiPr2)Mg(TMP)] 3 and [(TMEDA)Na(TMP)(m-C6H4NEt2)Mg(TMP)] 4 and two homometallic complexes [{(TMEDA)Na(EtNC6H5)}2] 5 and [(TMEDA)Na2(TMP)(C6H5PEt)]2 6 derived from homometallic metallation have been crystallographically characterised. Complex 6 is an unprecedented sodium-amide, sodium-phosphide hybrid with a rare (NaNNaP)2 ladder motif. These products reveal contrasting heterobimetallic deprotonation with homometallic induced ethene elimination reactivity. Solution studies of metallation mixtures and electrophilic iodine quenching reactions confirmed the metallation sites. In an attempt to rationalise the regioselectivity of the magnesiation reactions the C−H acidities of the six substrates were determined in THF solution using DFT calculations employing the M06-2X functional and cc-pVTZ Dunning's basis set.

KW - anilines

KW - dialkylphenyphosphines

KW - metallation

KW - regioselectivity

KW - synergistic effect

UR - http://www.scopus.com/inward/record.url?scp=85053707478&partnerID=8YFLogxK

U2 - 10.1002/chem.201803477

DO - 10.1002/chem.201803477

M3 - Article

SN - 0947-6539

VL - 24

SP - 15669

EP - 15677

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 58

ER -

Contrasting Synergistic Heterobimetallic (Na–Mg) and Homometallic (Na or Mg) Bases in Metallation Reactions of Dialkylphenylphosphines and Dialkylanilines: Lateral versus Ring Selectivities

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