Studies on the terpenoids and related alicyclic compounds XXXIX. A synthesis of .ALPHA.-methylene-.GAMMA.-lactones fused to medium and large rings by intramolecular cyclization of formylated allyl halides.
Concise Access to a Model of the Marine Alkaloid Halicyclamine A through Macrocycle-Forming Addition of a 5-Aminopenta-2,4-dienal onto a 2,3-Dihydropyridinium Salt
A biomimetic synthesis of a model compound for the marinealkaloidhalicyclamine A is reported that involves a macrocyclization through the intramolecular addition of a 5‐aminopenta‐2,4‐dienal onto a 2,3‐dihydropyridinium salt generated in situ (see scheme). In this way, a monomacrocyclic model, with the same relative stereochemistry as that of the natural product, was obtained.