Total Synthesis of Fostriecin (CI-920) We thank Professor Andrew G. Myers and Scott E. Schaus for helpful discussions, and Dr. Alexandra E. Gould and Isabel K. Reichardt for important preliminary experimental work. We also thank Dr. Robert J. Schultz of the Drug Synthesis and Chemistry Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer institute, for a sample of natural fostriecin. This work was supported by the NIH (GM-59316), and by Beinecke Memorial and NSF predoctoral fellowships to D.E.C.