Triple organocascade

Woodward probably conducted the most outstanding work on iminium catalysis before its rebirth in 2000. In this work. Woodward applied proUne catalysis in a triple organocascade reaction consisting of a deracemization (via aretro-Michael, Michael addition) and an intramolecular aldol reaction that determine the stereochemical outcome of the reaction (Scheme 1.5), leading to the synthesis of erythromycin [13]. 

Scheme 33.2 Triple organocascade reaction reported by Woodward.

Despite its operational simplicity (all the reagents were mixed together in the presence of the catalyst and without any precautions for excluding moisture from the reaction vessel), the mechanism of the triple organocascade (depicted in... 

Figure 42.3 Catalytic machinery of the Enders triple organocascade.

Scheme 42.17 Synthetic potential of the triple organocascade (a) forging all-carbon quaternary stereocenters, (b) and (c) construction of highly strained spirocyclic structures. The key nucleophilic intermediate...

By intensively studying the triple organocascade of aldehydes and nitroalkenes, researchers have been able to elucidate and appreciate the reactivity and mechanism of its individual processes. This has led to a more complex MCR, where the course of the domino reaction is controlled and altered simply by modulating the substrate concentration [52]. Two completely distinct domino processes were produced by combining different amounts of (x,P-unsaturated aldehyde 58 with... 

---