lithium tetramethylpiperidide
{{Chembox
| Watchedfields = changed
| verifiedrevid = 450705644
| ImageFile = Lithium 2,2,6,6-tetramethylpiperidide.png
| ImageFile_Ref = {{Chemboximage|correct|??}}
| ImageSize = 244
| ImageName = Structural formula of lithium tetramethylpiperidide
| IUPACName = Lithium tetramethylpiperidide
| SystematicName = 1-Lithio-2,2,6,6-tetramethylpiperidine
|Section1={{Chembox Identifiers
| CASNo = 38227-87-1
| CASNo_Ref = {{cascite|correct|??}}
| PubChem = 11051814
| ChemSpiderID = 21428984
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| SMILES = [Li]N1C(C)(C)CCCC1(C)C
| SMILES1 = CC1(C)CCCC(C)(C)N1[Li]
| SMILES2 = CC1(C)CCCC(C)(C)[N+]01[Li-][N+]1(C(C)(C)CCCC1(C)C)[Li-][N+]1(C(C)(C)CCCC1(C)C)[Li-][N+]1([Li-]0)C(C)(C)CCCC1(C)C
| SMILES2_Comment = Cyclic tetramer
| StdInChI = 1S/C9H18N.Li/c1-8(2)6-5-7-9(3,4)10-8;/h5-7H2,1-4H3;/q-1;+1
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = ANYSGBYRTLOUPO-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
|Section2={{Chembox Properties
| Formula = {{chem2|LiC9H18N}}
| Li=1|C=9|H=18|N=1
| pKa = 37
}}
}}
Lithium tetramethylpiperidide (often abbreviated LiTMP or LTMP) is a chemical compound with the molecular formula {{chem2|LiC9H18N}}. It is used as a non-nucleophilic base, being comparable to LiHMDS in terms of steric hindrance.
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.[http://www.chem.wisc.edu/areas/reich/Handouts/lireagents/amidebases.pdf amide primer] H. J. Reich 2002 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.{{cite journal |author1=M.F. Lappert |author2=M.J. Slade |author3=A. Singh |author4=J.L. Atwood |author5=R.D. Rogers |author6=R. Shakir |journal=Journal of the American Chemical Society |year= 1983 |volume=105 |issue=2 |pages=302–304 |title= 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) |doi=10.1021/ja00340a031}}
