Abstract: A neutral and relatively simple new method for effecting internal macrocyclic esterification of w-hydroxycarboxylic acids, based on a tin “template-driven” extrusion process, is discussed and its application to the synthesis (macrocyclization step) of the macrolide antibiotics zearalenone, ingramycin, and nodusmicin detailed. An efficient, formal total synthesis of pyrenophorin using this technique is also presented. Attemps to extend ...