Enantioselective Allylation of (2 E ,4 E )‐2,4‐Dimethylhexadienal: Synthesis of (5 R ,6 S )‐(+)‐Pteroenone

Allylation, trans‐ and cis‐ crotylation of (2 E ,4 E )‐2,4‐dimethylhexadienal, a representative α,β,γ,δ‐unsaturated aldehyde, was carried out under different catalytic and stoichiometric conditions. The reactions catalyzed by organocatalysts TRIP‐PA and N , N ′‐dioxides gave the best results with respect to yields, asymmetric induction, and catalyst load in comparison to other procedures. The developed methodology was applied in the enantioselective synthesis of (5 R ,6 S )‐(+)‐pteroenone, a defensive metabolite (ichthyodeterrent) of the Antarctic pteropod Clione antarctica .