Total Synthesis of the Pentacyclopropane Antifungal Agent FR-900848

Quatercyclopropane 31 was oxidized, homologated, reduced, and monocyclopropanated to provide the pentacyclopropane alcohol 35. Subsequent deoxygenation of alcohol 35 was effected using N-(phenylthio)succinimide (24) and tributylphosphine followed by Raney nickel desulfurization and deprotection to produce the alcohol 3. This was oxidized, homologated, and hydrolyzed to provide the fatty acid 2. BOP-Cl-mediated coupling of acid 2 and the nucleoside amine 40 gave amide 1, which was spectroscopically identical with an authentic sample of FR-900848 (1).