Abstract: Sarcodictyin A and B, eleutherobin, and bioactive analogs thereof synthesized using solid phase and solution phase chemistries. The synthetic method employs an attachment of common precursors, e.g., compounds 1880 or 200, on a solid support for generating conjugates 230 and 240, followed by standard chemical manipulations. A combinatorial library of sarcodictyins and eletherobin analogs was constructed with modified C-8 ester, C-15 ester and C-4 ketal functionalities and was screened for activity with respect to tubulin polymerization and cytotoxic activity against tumor cells, including Taxol-resistant lines. Compounds 600, 610, 630, 660-700, 730, 760, 850, and 920 were identified to be of equal or superior biological activities as compared to their corresponding natural product.