Abstract
The electron-withdrawing aptitude displayed by the acyl group makes N -acylamines very attractive substrates in many processes aimed at the preparation of amino derivatives. The remarkable electrophilicity of N -acylimines can be profitably used to overcome reactivity troubles often observed using N -alkylimines and N -arylimines. The presence of a polar acyl moiety on the nitrogen atom is particularly effective in stereoselective reactions were electrostatic interactions play a major role in determining the facial preference for the nucleophilic attack. Utilization of alkoxycarbonyl groups (e.g. Boc or Cbz) as activating N -acyl substituents allows one to obtain the final amino derivative in a protected form that can be readily cleaved under mild conditions. In this review, several synthetic applications of N -acylimines in stereoselective reactions that have appeared in the literature since 1990 are discussed.
1 Introduction
2 Preparation of N -Acylimines
3 Nucleophilic Additions to N -Acylimines
3.1 Reaction with Organometallic Reagents and Related Carbanions
3.1.1 Linear N -Acylimines
3.1.2 Cyclic N -Acylimines
3.2 Reaction with Enolate Anions
3.2.1 Nitroalkanes: The Aza-Henry Reaction
3.2.2 1,3-Dicarbonyls
3.2.3 Carbonyls and Related Derivatives
3.2.4 Carboxylic Acid Derivatives
3.3 Reaction with Aromatic Compounds
3.4 Reaction with Heteronucleophiles
4 Cycloaddition Reactions
5 Conclusion
Key words
amines - asymmetric synthesis - catalysis - imines - nucleophilic addition
