Proline‐Catalyzed Imino‐Diels–Alder Reactions: Synthesis of meso‐2,6‐Diaryl‐4‐piperidones

Abstract

Amine-catalyzed imino-Diels-Alder reactions of acyclic a,b-unsaturated ketones with imines have been developed. l-Proline catalyzed the in situ generation of 2-amino-1,3-butadienes to provide a stereoselective synthesis of meso-2,6-diaryl-4-piperidones in one direct step.

Enzyme-Catalyzed Direct Three-Component Aza-Diels–Alder Reaction Using Hen Egg White Lysozyme

“…Generally, it is believed that the aza-Diels−Alder reaction proceeds via a Mannich−Michael process rather than a concerted manner, and the in situ generated imine participates in the mannich reaction as an electrophile. 10 In the present study, all of the reactions involved in situ formation of the imine from aldehyde and amine. In order to know whether the imine could be used directly in this enzymatic reaction, the experiments using imine in place of aldehyde and amine were performed (Table 11).…”

Mannich–Michael versus formal aza-Diels–Alder approaches to piperidine derivatives

“…Regarding the organocatalyst, Aznar et al also screened the aza-Diels-Alder reaction against the pyrrolidine derived catalysts 191 and 192. 94 Both of these catalysts were ineffective by themselves in the reaction between enone 178 and imine 179. 180 was formed in 58% and 61% yields respectively.…”

One-Pot Synthesis of Substituted Piperidinones and 3,4-Dihydropyrimidinones Using a Highly Active and Recyclable Supported Ionic Liquid Phase Organocatalyst

“…The use of L-proline, as a homogeneous catalyst, for the synthesis of piperidinones is well explored in literature. [30,31] Our method involves the use of L-proline and ionic liquid in heterogeneous form, resulting in enhanced catalytic activity and recyclability, thus making the process eco-friendly. Keeping in view the importance of piperidinones and pyrimidinones and the scope of SILPC, we wish to report an efficient method for the synthesis of 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO 4 ] and its supported ionic liquid phase organocatalyst form, silica-L-proline [EMIM][EtSO 4 ] (SILPOC).…”