Toward the total synthesis of scytophycins: Synthesis of the C7–C21 fragments of scytophycins A, B, and C

[Display omitted] Scytophysins are cytotoxic macrolides with a 22-membered ring and are characterized by their strong cytotoxicities targeting cytoskeletal protein actin. Toward the comprehensive total synthesis of scytophycins, we have investigated the late-state functionalization using fragment compounds. We established stereoselective construction of the C7-C21 part in scytophycins A and B involving characteristic C16 epoxide by using Sharpless epoxidation. Although stereoselectivity remains unsatisfactory, reduction of the C16 exo-olefin for the synthesis of scytophycin C was achieved.