The Origin of Chemical and Configurational Stability of Chiral Nonracemic Tert-Butyl Aziridinecarboxylate Anions
Résumé
The origin of good chemical and configurational stability of aziridine ester anions derived from (R)-(-)-phenylglycinol has been investigated. Kinetic acidity seems to play an important role in the deprotonation step and chemical stability of the anionic species. Spectroscopic investigations showed that the good overall retention of configuration was governed by the directing effect of the nitrogen atom, which acts as a stereogenic centre in the alkylation step of the enolate intermediate.