Convergent synthesis of the ABCDE-ring fragment of the Caribbean ciguatoxin C-CTX-1

Ciguatoxin C-CTX-1 was isolated as a principal causative toxin of ciguatera seafood poisoning in the Caribbean Sea, and is structurally classified as a ladder-shaped polycyclic ether. In this Letter, we report the convergent synthesis of the pentacyclic left half of C-CTX-1, based on a newly developed acyl radical strategy.