Ihe prochiral lithium 2,2,6-trimethylcyclohexenolate (2) was prepared from ketone 1 by deprotonation with lithium (S,S)-a,a'-dimethyldibenzylamide(4). Reaction of 2 with carbon dioxide at low temperature followed by methylation with metFy1 iodide yielded the corresponding ester 3 with an e.e. of 67%
Solution structures of a monodentate chiral lithium amide in the presence of lithium halide
โ Scribed by Keizo Sugasawa; Mitsuru Shindo; Hiroshi Noguchi; Kenji Koga
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- French
- Weight
- 232 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0040-4039
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๐ SIMILAR VOLUMES
Enantioselective alkylation of lactams and lactones can be realized up to 98% ee by deprotonation with a chiral tetradentate lithium amide (4b) in the presence of lithium bromide, and subsequent alkylation with active alkylating agents in non-chelating solvents.
Lithium bis(N,N-dimethyl-2-aminoethyl)amide (1 a) and lithium N-methyl-N- (3,6-diaza-3,6-dimethyl)heptylamide (2) are dimers in toluene, THF and in the crystalline state where they exhibit diamond-shaped Li 2 N 2 cores. Tetracoordination of lithium is achieved by intramolecular binding of the amine