DescriptionDisclosed are studies directed towards the total synthesis of (9S)-dihydroerythronolide A. Towards this goal an advanced intermediate, 14 member bis[allene] macrolactone was synthesized. A general method of cuprate-mediated carbon nucleophile delivery to spirodiepoxides was developed. An unprecedented macrolactonization to form bis[allene] macrolactone and macrocyclic stereocontroled epoxidation of this system was achieved. In a separate study, the highly stereocontroled formation of spirodiepoxides and excellent regiocontroled spirodiepoxide opening was developed. This method relies upon the presence of a silyl substituent on the allene. This finding was applied to the total synthesis of epicitreodiol.