We (a) describe the completion of a total synthesis of 7,11-
epi-thyrsiferol (
4), (b) compare the antimitoticactivities of thyrsiferol (
2),
15,28-dehydrothyrsiferol (
3), and 7,11-
epi-thyrsiferol (
4), (c) evaluate thesynergistic behavior of the title compound and colchicine to inhibit cell proliferation, and (d) describethe results of conformational searches that provide additional insight concerning the SAR profile of thethyrsiferol family of natural products.