Lithium tetramethylpiperidide
Lithium tetramethylpiperidide (often abbreviated LiTMP or LTMP) is a chemical compound with the molecular formula C9H18LiN. It is used as a non-nucleophilic base, being comparable to LiHMDS in terms of pKa and steric hindrance, to favor elimination reactions.
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| Names | |
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| IUPAC name
Lithium tetramethylpiperidide | |
| Systematic IUPAC name
1-Lithio-2,2,6,6-tetramethylpiperidine | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.209.926 |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| C9H18LiN | |
| Molar mass | 147.19 g·mol−1 |
| Acidity (pKa) | 37 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
Synthesis
It is synthesised by the deprotonation of 2,2,6,6-tetramethylpiperidine with n-butyllithium at −78 °C. Recent reports show that this reaction can also be performed 0 °C.[1] The compound is stable in a THF/ethylbenzene solvent mixture and is commercially available as such.
Structure
Like many lithium reagents it has a tendency to aggregate, forming a tetramer in the solid state.[2]
See also
References
- amide primer H. J. Reich 2002
- M.F. Lappert; M.J. Slade; A. Singh; J.L. Atwood; R.D. Rogers; R. Shakir (1983). "Structure and reactivity of sterically hindered lithium amides and their diethyl etherates: crystal and molecular structures of [Li{N(SiMe3)2}(OEt2)]2 and tetrakis(2,2,6,6-tetramethylpiperidinatolithium)". Journal of the American Chemical Society. 105 (2): 302–304. doi:10.1021/ja00340a031.
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