Insight into the Behaviour of a Lithium Enolate in Solution

(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.