Large-scale synthesis, design, and structure-activity relationships of khafrefungin are reported. Khafrefungin is an antifungal agent that inhibitsinositolphosphorylceramide (IPC) synthase, an enzyme involved in fungal sphingolipid biosynthesis. Unlike other inhibitors that inhibit the corresponding enzyme in fungi and mammals to the same extent, khafrefungin does not impair sphingolipid synthesis in mammals