Synthesis and Conformational Analysis of Macrocyclic Dilactones Mimicking the Pharmacophore of Aplysiatoxin

A small number of macrocyclic dilactones of type 3 , i.e. , 9, 10, 11 , and epi‐ 11 , comprising a 3,4‐dihydroxypentanoic acid unit, the pharmacophore of aplysiatoxin, and a conformationally preorganized ω ‐hydroxynonanoic acid unit were synthesized. Conformational analysis – based on 2 J and 3 J NMR coupling constants – of the dihydroxypentanoyl part of these macro‐dilactones indicates the extent to which a conformation induction across the macro‐dilactone ring occurs from the stereogenic centres implemented in the ω ‐hydroxynonanoic acid part.