ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Degree of Aggregation of Organolithium Compounds by Means of Cryoscopy in TetrahydrofuranThe association behaviour of alkyl-, aryl- and alkinyl-lithium compounds as well as of lithium enolates and chiral lithium azaenolates is determined from freezing-point depression values in dilute tetrahydrofuran solutions at -108°C. Compared toX-ray-crystallographic data (lithiated methyldithiane, phenyllithium, lithio derivatives of a ketone, carboxylic amide and -ester, and a diketopiperazine-bislactim-ether), desaggregation is found under these conditions. The structures determined by 13C-NMR spectroscopy for BuLi, lithiophenylacetylene and (t-butyl)lithioacetylene are confirmed. The dilithio salt of a carboxylic acid is polymeric, a chiral lithio-hydrazone and a chiral lithio-oxazolidine are monomeric and dimeric, respectively. Lithium diisopropylamide is a monomer-dimer equilibrium mixture. The apparatus described permits both synthesis and measurement of the reactive species under inert atmosphere conditions in the same vessel.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19840670736
