X-ray crystallographic studies and comparative reactivity studies of a sodium diisopropylamide (NDA) complex and related hindered amides

Philip C. Andrews, N.D.R. Barnett, Robert Mulvey, W. Clegg, P.A. O'Neil, Donald Barr, Lucy Cowton, Andrea J. Dawson, Basil J. Wakefield

Research output: Contribution to journalArticle

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Abstract

Two related sodium amide complexes derived from secondary amines with bulky organic substituents have been synthesised and crystallographically characterised. Both [(Pr-i)(2)NNa(TMEDA)](2) and [Cy(Pr-i)NNa(TMEDA)](2) adopt dimeric crystal structures with a central, planar (nitrogen-metal)(2) azametallocycle, a now familiar feature in both lithium amide and sodium amide chemistry. TMEDA ligands chelate in their usual bidentate manner making the Na+ cations four-coordinate with a distorted tetrahedral geometry. In the latter complex, the amido substituents are disposed in a trans conformation with respect to the (NNa)(2) ring plane. The deprotonating ability of the former complex has been tested against that of the parent amide [(Pr-i)(2)NNa](infinity) and the lithium congener [(Pr-i)(2)NLi](infinity) (LDA) in a series of simple organic reactions: selective enolate formation from 2-octanone and 2-methylcyclohexanone; synthesis of diphenylacetic acid via diphenylmethane. In general, the performance of the sodium reagents compares favourably with that of the lithium reagent.

LanguageEnglish
Pages85-95
Number of pages11
JournalJournal of Organometallic Chemistry
Volume518
Issue number1-2
DOIs
Publication statusPublished - 12 Jul 1996

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Amides
amides
reactivity
Sodium
Lithium
sodium
X-Rays
X rays
lithium
infinity
reagents
x rays
congeners
chelates
Amines
Conformations
Cations
amines
Nitrogen
Crystal structure

Keywords

  • lithium
  • sodium
  • amide
  • crystal structure
  • lithium diisopropylamide
  • ladder
  • solid state
  • hexamethylphosphoric triamide
  • enolate formation
  • ring

Cite this

Andrews, Philip C. ; Barnett, N.D.R. ; Mulvey, Robert ; Clegg, W. ; O'Neil, P.A. ; Barr, Donald ; Cowton, Lucy ; Dawson, Andrea J. ; Wakefield, Basil J. / X-ray crystallographic studies and comparative reactivity studies of a sodium diisopropylamide (NDA) complex and related hindered amides. In: Journal of Organometallic Chemistry. 1996 ; Vol. 518, No. 1-2. pp. 85-95.
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abstract = "Two related sodium amide complexes derived from secondary amines with bulky organic substituents have been synthesised and crystallographically characterised. Both [(Pr-i)(2)NNa(TMEDA)](2) and [Cy(Pr-i)NNa(TMEDA)](2) adopt dimeric crystal structures with a central, planar (nitrogen-metal)(2) azametallocycle, a now familiar feature in both lithium amide and sodium amide chemistry. TMEDA ligands chelate in their usual bidentate manner making the Na+ cations four-coordinate with a distorted tetrahedral geometry. In the latter complex, the amido substituents are disposed in a trans conformation with respect to the (NNa)(2) ring plane. The deprotonating ability of the former complex has been tested against that of the parent amide [(Pr-i)(2)NNa](infinity) and the lithium congener [(Pr-i)(2)NLi](infinity) (LDA) in a series of simple organic reactions: selective enolate formation from 2-octanone and 2-methylcyclohexanone; synthesis of diphenylacetic acid via diphenylmethane. In general, the performance of the sodium reagents compares favourably with that of the lithium reagent.",
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X-ray crystallographic studies and comparative reactivity studies of a sodium diisopropylamide (NDA) complex and related hindered amides. / Andrews, Philip C.; Barnett, N.D.R.; Mulvey, Robert; Clegg, W.; O'Neil, P.A.; Barr, Donald; Cowton, Lucy; Dawson, Andrea J.; Wakefield, Basil J.

In: Journal of Organometallic Chemistry, Vol. 518, No. 1-2, 12.07.1996, p. 85-95.

Research output: Contribution to journalArticle

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T1 - X-ray crystallographic studies and comparative reactivity studies of a sodium diisopropylamide (NDA) complex and related hindered amides

AU - Andrews, Philip C.

AU - Barnett, N.D.R.

AU - Mulvey, Robert

AU - Clegg, W.

AU - O'Neil, P.A.

AU - Barr, Donald

AU - Cowton, Lucy

AU - Dawson, Andrea J.

AU - Wakefield, Basil J.

PY - 1996/7/12

Y1 - 1996/7/12

N2 - Two related sodium amide complexes derived from secondary amines with bulky organic substituents have been synthesised and crystallographically characterised. Both [(Pr-i)(2)NNa(TMEDA)](2) and [Cy(Pr-i)NNa(TMEDA)](2) adopt dimeric crystal structures with a central, planar (nitrogen-metal)(2) azametallocycle, a now familiar feature in both lithium amide and sodium amide chemistry. TMEDA ligands chelate in their usual bidentate manner making the Na+ cations four-coordinate with a distorted tetrahedral geometry. In the latter complex, the amido substituents are disposed in a trans conformation with respect to the (NNa)(2) ring plane. The deprotonating ability of the former complex has been tested against that of the parent amide [(Pr-i)(2)NNa](infinity) and the lithium congener [(Pr-i)(2)NLi](infinity) (LDA) in a series of simple organic reactions: selective enolate formation from 2-octanone and 2-methylcyclohexanone; synthesis of diphenylacetic acid via diphenylmethane. In general, the performance of the sodium reagents compares favourably with that of the lithium reagent.

AB - Two related sodium amide complexes derived from secondary amines with bulky organic substituents have been synthesised and crystallographically characterised. Both [(Pr-i)(2)NNa(TMEDA)](2) and [Cy(Pr-i)NNa(TMEDA)](2) adopt dimeric crystal structures with a central, planar (nitrogen-metal)(2) azametallocycle, a now familiar feature in both lithium amide and sodium amide chemistry. TMEDA ligands chelate in their usual bidentate manner making the Na+ cations four-coordinate with a distorted tetrahedral geometry. In the latter complex, the amido substituents are disposed in a trans conformation with respect to the (NNa)(2) ring plane. The deprotonating ability of the former complex has been tested against that of the parent amide [(Pr-i)(2)NNa](infinity) and the lithium congener [(Pr-i)(2)NLi](infinity) (LDA) in a series of simple organic reactions: selective enolate formation from 2-octanone and 2-methylcyclohexanone; synthesis of diphenylacetic acid via diphenylmethane. In general, the performance of the sodium reagents compares favourably with that of the lithium reagent.

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KW - amide

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KW - ladder

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KW - hexamethylphosphoric triamide

KW - enolate formation

KW - ring

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