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Lithium pyrrolidide

The existence of such complexes has been confirmed by kinetic experiments, multidimensional and multinuclear ( Li, H) NMR, and the beneficial effect of substitutions at the lithium pyrrolidide ring outlined . Nevertheless, recent computational studies... [Pg.1181]

Die Anwendung einer nur katalytischen Menge eines Lithium-amids (Lithium-pyrrolidid) ist fur die mit 90%iger Ausbeute verlaufende Reaktion von Benzophenon-methylimin mit Isopren zu 2,2-Diphenyl-3-isopropenyl-pyrrolidin beschrieben3. [Pg.1048]

In the presence of the corresponding pyrrolidine diamine, the chiral lithium pyrrolidide amide yields dimeric chelates composed of a lithium pyrrolidide amide dimer solvated by a pyrrolidine diamine, (Li-6)2 6, as shown by NMR spectroscopy39. The lithium amide gives two 6Li NMR signals in a 1 1 ratio. The addition of TMEDA to Li-6 results in a similar complex where TMEDA coordinates to the lithium pyrrolidide amide dimer, (Li-6)2 TMEDA. [Pg.388]

Unlike this reaction, the reaction of OFN with lithium dialkylamides easily proceeds at ambient temperature and results in the formation of hexa- 73-75 or heptaamines 76 and 77 in 41-46% yield63. The reaction occurs smoothly and selectively in dioxane or THF with two-fold excess of lithium dialkylamide per each fluorine atom. It is also recommended that UMPA be added to the reaction mixture (2 equivalents per 1 equivalent of the lithium amide), since cyclic ether solvents are prone to interact with non-solvated lithium amides and thus to form ring-opening products that then react with OFN. Lithium piperidide in either dioxane or THF gives exclusively the hexa-substituted derivative 75. Lithium dimethylamide produces hexaamine 73 in dioxane and heptaamine 76 in THF, whereas the most reactive lithium pyrrolidide forms in dioxane almost a 1 1 mixture of polyamines 74 and 77, and the only product in THF is 77. [Pg.943]

Dienes. Japanese chemists have prepared 1,5-dienes by reductive coupling of allylic haUdes with these complexes. For example, reaction of cyclohexylidenethyl bromide with the complex of lithium pyrrolidide and cuprous iodide in ether at 0° for 4 hr. gives the three products shown in equation I in essentially quantitative yield. The reaction is very sensitive, however, to the solvent and the temperature and also to the dialkylamine used for preparation of the catalyst. [Pg.327]

Related Reagents. Lithium Amide Lithium Hexamethyl-disilazide Lithium Diethylamide Lithium Piperidide Lithium Pyrrolidide Lithium 2,2,6,6-tetramethylpiperidide Potassium Diisopropylamide. [Pg.237]

Related Reagents. Lithium diethylamide lithium diisopro-pylamide lithium piperidide lithium pyrrolidide lithium 2,2,6,6-tetramethylpiperidide. [Pg.366]

In summary, chelating chiral lithium amides exist in either of four major structural motifs or mixtures of them (Scheme 3). Non-coordinating solvents generally favor cyclic trimers, A. Ladder tetramers are favored for pyrrolidide amides in the absence of coordinating solvents. [Pg.391]


See other pages where Lithium pyrrolidide is mentioned: [Pg.60]    [Pg.1181]    [Pg.663]    [Pg.110]    [Pg.3041]    [Pg.300]    [Pg.1710]    [Pg.1710]    [Pg.327]    [Pg.1912]    [Pg.446]    [Pg.493]    [Pg.60]    [Pg.1181]    [Pg.663]    [Pg.110]    [Pg.3041]    [Pg.300]    [Pg.1710]    [Pg.1710]    [Pg.327]    [Pg.1912]    [Pg.446]    [Pg.493]    [Pg.97]    [Pg.272]    [Pg.196]    [Pg.219]    [Pg.109]   
See also in sourсe #XX -- [ Pg.327 ]




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Pyrrolidides

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