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

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (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 languageEnglish
Pages (from-to)15669-15677
Number of pages9
JournalChemistry - A European Journal
Volume24
Issue number58
DOIs
Publication statusPublished - 17 Oct 2018

Keywords

  • anilines
  • dialkylphenyphosphines
  • metallation
  • regioselectivity
  • synergistic effect

Cite this

@article{bb8329c404184361b5e6a19566980897,
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.}",
year = "2018",
month = "10",
day = "17",
doi = "10.1002/chem.201803477",
language = "English",
volume = "24",
pages = "15669--15677",
journal = "Chemistry - A European Journal",
issn = "1521-3765",
publisher = "Wiley-VCH Verlag GmbH & Co. KGaA",
number = "58",

}

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.; Izgorodina, Ekaterina I.; Mulvey, Robert E.; Blair, Victoria L.

In: Chemistry - A European Journal, Vol. 24, No. 58, 17.10.2018, p. 15669-15677.

Research output: Contribution to journalArticleResearchpeer-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

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DO - 10.1002/chem.201803477

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