Organocatalytic Cascade Synthesis of Decahydroquinolines

Significance

Reported is the highly diastereoselective organocatalytic multicomponent cascade synthesis of a series of decahydroquinolines. A mechanism is proposed involving reaction of the organocatalyst with cyclohexanone to form an imine, which then undergoes a highly stereo­selective Michael-type addition to the nitroalkene. The resulting adduct then reacts with the N-Ts im­ine in an aza-Henry reaction, the product of which then undergoes cyclization via hemiaminalization to yield the observed products. Although no evidence is given for this mechanism, it is reasonable given the highly stereoselective nature of the reaction.