Amine-catalyzed direct self Diels-Alder reactions of α,β-unsaturated ketones in water: Synthesis of pro-chiral cyclohexanones

Abstract

Amine-catalyzed direct self Diels-Alder reactions of α,β-unsaturated ketones have been developed. (S)-1-(2-Pyrrolidinyl-methyl)pyrrolidine, L-proline and pyrrolidine catalyzed the reaction of α,β-unsaturated ketones to provide cyclohexanone derivatives with good yield (up to 80%) in a single step via in situ-generation of 2-amino-1,3-butadienes and iminium ion-activated enones. Pro-chiral cyclohexanones were selectively prepared with pyrrolidine catalysis in water. © 2002 Published by Elsevier Science Ltd.