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Insight into the Behaviour of a Lithium Enolate in Solution
Author(s) -
Strazewski Peter,
Tamm Christoph
Publication year - 1986
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19860690512
Subject(s) - chemistry , deprotonation , lithium diisopropylamide , toluene , amine gas treating , lithium (medication) , medicinal chemistry , acetic acid , organic chemistry , ion , medicine , endocrinology
(2 S ,4 S )‐2‐( tert ‐Butyl)‐5‐oxo‐1,3‐dioxolan‐4‐acetic acid ( 1 ) was dilithiated to the enolate 2 in toluene and THF with lithium diisopropylamide (LiN(i‐Pr) 2 ) under various conditions. Deuteration experiments with 2 showed that two different stable forms of the enolate could be produced, depending on whether the deprotonation of 1 had been carried out in toluene or THF. The generated (i‐Pr) 2 NH was coordinated to the enolate and, hence, served as a strong lipophilic solvating agent. LiN(i‐Pr) 2 could substitute the amine ligands of the two species to a different extent. THF was partially able to displace (i‐Pr) 2 NH that solvated the species produced in toluene, but the coordination of the amine to the one produced in THF was quantitive. Correlations with given explanations are made.