Alkali-metal-mediated manganation(ii) of functionalized arenes and applications of ortho-manganated products in pd-catalyzed cross-coupling reactions with iodobenzene

V.L. Blair, W. Clegg, B. Conway, E. Hevia, A. Kennedy, J. Klett, R.E. Mulvey, L. Russo

Research output: Contribution to journalArticle

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Abstract

Extending the recently introduced concept of alkali-metal-mediated manganation to functionalised arenes, the heteroleptic sodium manganate reagent [(tmeda)Na(tmp)(R)Mn(tmp)] (1; TMEDA=N,N,N,N-tetramethylethylenediamine, TMP=2,2,6,6-tetramethylpiperidide, R=CH2SiMe3) has been treated with anisole or N,N-diisopropylbenzamide in a 1:1 stoichiometry in hexane. These reactions afforded the crystalline products [(tmeda)Na(tmp)(o-C6H4OMe)Mn(tmp)] (2) and [(tmeda)Na(tmp){o-{C(O)N(iPr)2C6H4}Mn(CH2SiMe3)] (3), respectively, as determined from X-ray crystallographic studies. On the basis of these products, it can be surmised that reagent 1 has acted, at least partially and ultimately, as an alkyl base in the first reaction liberating the silane Me4Si, but as an amido base in the second reaction liberating the amine TMPH. Both of these paramagnetic products 2 and 3 have contacted ion-pair structures, the key features of which are six-atom, five-element (NaNMnCCO) and seven-atom, five-element (NaNMnCCCO) rings, respectively. Manganates 2 and 3 were successfully cross-coupled with iodobenzene under [PdCl2(dppf)] (dppf=1,1-bis(diphenylphosphino)ferrocene) catalysis to generate unsymmetrical biaryl compounds in yields of 98.0 and 66.2 %, respectively. Emphasizing the importance of alkali-metal mediation in these manganation reactions, the bisalkyl Mn reagent on its own fails to metalate the said benzamide, but instead produces the monomeric, donor-acceptor complex [Mn(R)2{(iPr)2NC(Ph)(O)}2] (5), which has also been crystallographically characterised. During one attempt to repeat the synthesis of 2, the butoxide-contaminated complex [{(tmeda)Na(R)(OBu)(o-C6H4OMe)Mn}2] (6) was obtained. In contrast to 2 and 3, due to reduced steric constraints, this complex adopts a dimeric arrangement in the crystal, the centrepiece of which is a twelve atom (NaOCCMnC)2 ring.
LanguageEnglish
Pages65-72
Number of pages7
JournalChemistry - A European Journal
Volume14
Issue number1
DOIs
Publication statusPublished - 2008

Fingerprint

Alkali Metals
Atoms
Thymidine Monophosphate
Silanes
Hexanes
Stoichiometry
Catalysis
Amines
Sodium
Ions
Crystalline materials
X rays
Crystals
iodobenzene

Keywords

  • aromatic compounds
  • cross-coupling
  • manganese
  • metalation
  • sodium

Cite this

@article{bb5fd9b92d3a42fda97f625a35a0229e,
title = "Alkali-metal-mediated manganation(ii) of functionalized arenes and applications of ortho-manganated products in pd-catalyzed cross-coupling reactions with iodobenzene",
abstract = "Extending the recently introduced concept of alkali-metal-mediated manganation to functionalised arenes, the heteroleptic sodium manganate reagent [(tmeda)Na(tmp)(R)Mn(tmp)] (1; TMEDA=N,N,N,N-tetramethylethylenediamine, TMP=2,2,6,6-tetramethylpiperidide, R=CH2SiMe3) has been treated with anisole or N,N-diisopropylbenzamide in a 1:1 stoichiometry in hexane. These reactions afforded the crystalline products [(tmeda)Na(tmp)(o-C6H4OMe)Mn(tmp)] (2) and [(tmeda)Na(tmp){o-{C(O)N(iPr)2C6H4}Mn(CH2SiMe3)] (3), respectively, as determined from X-ray crystallographic studies. On the basis of these products, it can be surmised that reagent 1 has acted, at least partially and ultimately, as an alkyl base in the first reaction liberating the silane Me4Si, but as an amido base in the second reaction liberating the amine TMPH. Both of these paramagnetic products 2 and 3 have contacted ion-pair structures, the key features of which are six-atom, five-element (NaNMnCCO) and seven-atom, five-element (NaNMnCCCO) rings, respectively. Manganates 2 and 3 were successfully cross-coupled with iodobenzene under [PdCl2(dppf)] (dppf=1,1-bis(diphenylphosphino)ferrocene) catalysis to generate unsymmetrical biaryl compounds in yields of 98.0 and 66.2 {\%}, respectively. Emphasizing the importance of alkali-metal mediation in these manganation reactions, the bisalkyl Mn reagent on its own fails to metalate the said benzamide, but instead produces the monomeric, donor-acceptor complex [Mn(R)2{(iPr)2NC(Ph)(O)}2] (5), which has also been crystallographically characterised. During one attempt to repeat the synthesis of 2, the butoxide-contaminated complex [{(tmeda)Na(R)(OBu)(o-C6H4OMe)Mn}2] (6) was obtained. In contrast to 2 and 3, due to reduced steric constraints, this complex adopts a dimeric arrangement in the crystal, the centrepiece of which is a twelve atom (NaOCCMnC)2 ring.",
keywords = "aromatic compounds, cross-coupling, manganese, metalation, sodium",
author = "V.L. Blair and W. Clegg and B. Conway and E. Hevia and A. Kennedy and J. Klett and R.E. Mulvey and L. Russo",
year = "2008",
doi = "10.1002/chem.200701597",
language = "English",
volume = "14",
pages = "65--72",
journal = "Chemistry - A European Journal",
issn = "0947-6539",
number = "1",

}

Alkali-metal-mediated manganation(ii) of functionalized arenes and applications of ortho-manganated products in pd-catalyzed cross-coupling reactions with iodobenzene. / Blair, V.L.; Clegg, W.; Conway, B.; Hevia, E.; Kennedy, A.; Klett, J.; Mulvey, R.E.; Russo, L.

In: Chemistry - A European Journal, Vol. 14, No. 1, 2008, p. 65-72.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Alkali-metal-mediated manganation(ii) of functionalized arenes and applications of ortho-manganated products in pd-catalyzed cross-coupling reactions with iodobenzene

AU - Blair, V.L.

AU - Clegg, W.

AU - Conway, B.

AU - Hevia, E.

AU - Kennedy, A.

AU - Klett, J.

AU - Mulvey, R.E.

AU - Russo, L.

PY - 2008

Y1 - 2008

N2 - Extending the recently introduced concept of alkali-metal-mediated manganation to functionalised arenes, the heteroleptic sodium manganate reagent [(tmeda)Na(tmp)(R)Mn(tmp)] (1; TMEDA=N,N,N,N-tetramethylethylenediamine, TMP=2,2,6,6-tetramethylpiperidide, R=CH2SiMe3) has been treated with anisole or N,N-diisopropylbenzamide in a 1:1 stoichiometry in hexane. These reactions afforded the crystalline products [(tmeda)Na(tmp)(o-C6H4OMe)Mn(tmp)] (2) and [(tmeda)Na(tmp){o-{C(O)N(iPr)2C6H4}Mn(CH2SiMe3)] (3), respectively, as determined from X-ray crystallographic studies. On the basis of these products, it can be surmised that reagent 1 has acted, at least partially and ultimately, as an alkyl base in the first reaction liberating the silane Me4Si, but as an amido base in the second reaction liberating the amine TMPH. Both of these paramagnetic products 2 and 3 have contacted ion-pair structures, the key features of which are six-atom, five-element (NaNMnCCO) and seven-atom, five-element (NaNMnCCCO) rings, respectively. Manganates 2 and 3 were successfully cross-coupled with iodobenzene under [PdCl2(dppf)] (dppf=1,1-bis(diphenylphosphino)ferrocene) catalysis to generate unsymmetrical biaryl compounds in yields of 98.0 and 66.2 %, respectively. Emphasizing the importance of alkali-metal mediation in these manganation reactions, the bisalkyl Mn reagent on its own fails to metalate the said benzamide, but instead produces the monomeric, donor-acceptor complex [Mn(R)2{(iPr)2NC(Ph)(O)}2] (5), which has also been crystallographically characterised. During one attempt to repeat the synthesis of 2, the butoxide-contaminated complex [{(tmeda)Na(R)(OBu)(o-C6H4OMe)Mn}2] (6) was obtained. In contrast to 2 and 3, due to reduced steric constraints, this complex adopts a dimeric arrangement in the crystal, the centrepiece of which is a twelve atom (NaOCCMnC)2 ring.

AB - Extending the recently introduced concept of alkali-metal-mediated manganation to functionalised arenes, the heteroleptic sodium manganate reagent [(tmeda)Na(tmp)(R)Mn(tmp)] (1; TMEDA=N,N,N,N-tetramethylethylenediamine, TMP=2,2,6,6-tetramethylpiperidide, R=CH2SiMe3) has been treated with anisole or N,N-diisopropylbenzamide in a 1:1 stoichiometry in hexane. These reactions afforded the crystalline products [(tmeda)Na(tmp)(o-C6H4OMe)Mn(tmp)] (2) and [(tmeda)Na(tmp){o-{C(O)N(iPr)2C6H4}Mn(CH2SiMe3)] (3), respectively, as determined from X-ray crystallographic studies. On the basis of these products, it can be surmised that reagent 1 has acted, at least partially and ultimately, as an alkyl base in the first reaction liberating the silane Me4Si, but as an amido base in the second reaction liberating the amine TMPH. Both of these paramagnetic products 2 and 3 have contacted ion-pair structures, the key features of which are six-atom, five-element (NaNMnCCO) and seven-atom, five-element (NaNMnCCCO) rings, respectively. Manganates 2 and 3 were successfully cross-coupled with iodobenzene under [PdCl2(dppf)] (dppf=1,1-bis(diphenylphosphino)ferrocene) catalysis to generate unsymmetrical biaryl compounds in yields of 98.0 and 66.2 %, respectively. Emphasizing the importance of alkali-metal mediation in these manganation reactions, the bisalkyl Mn reagent on its own fails to metalate the said benzamide, but instead produces the monomeric, donor-acceptor complex [Mn(R)2{(iPr)2NC(Ph)(O)}2] (5), which has also been crystallographically characterised. During one attempt to repeat the synthesis of 2, the butoxide-contaminated complex [{(tmeda)Na(R)(OBu)(o-C6H4OMe)Mn}2] (6) was obtained. In contrast to 2 and 3, due to reduced steric constraints, this complex adopts a dimeric arrangement in the crystal, the centrepiece of which is a twelve atom (NaOCCMnC)2 ring.

KW - aromatic compounds

KW - cross-coupling

KW - manganese

KW - metalation

KW - sodium

UR - http://dx.doi.org/10.1002/chem.200701597

U2 - 10.1002/chem.200701597

DO - 10.1002/chem.200701597

M3 - Article

VL - 14

SP - 65

EP - 72

JO - Chemistry - A European Journal

T2 - Chemistry - A European Journal

JF - Chemistry - A European Journal

SN - 0947-6539

IS - 1

ER -