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.
Original language | English |
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Pages (from-to) | 85-95 |
Number of pages | 11 |
Journal | Journal of Organometallic Chemistry |
Volume | 518 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 12 Jul 1996 |
Keywords
- lithium
- sodium
- amide
- crystal structure
- lithium diisopropylamide
- ladder
- solid state
- hexamethylphosphoric triamide
- enolate formation
- ring