Organocatalytic Enantio- and Diastereoselective 1,3-Dipolar Cycloaddition between Alanine-Derived Ketonitrones and E-Crotonaldehyde: Efficiency and Full Stereochemical Study
Résumé
Highly enantio- and exo-selective 1,3-dipolar cycloadditions of alanine-derived ketonitrones to E-crotonaldehyde could be realized in a good yield by the use of a chiral imidazolidinone salt without the addition of water. The origin of the stereoselectivity in the reaction was discussed and the absolute configuration of the cycloadduct determined unambiguously.