Convergent Synthesis of the WXYZA′B′C′D′E′F′ Ring Segment of Maitotoxin

Synthesis of the WXYZA′B′C′D′E′F′ ring segment of maitotoxin, a ladder-shaped polyether produced by the dinoflagellate Gambierdiscus toxicus, was achieved based on a convergent strategy via α-cyano ethers developed in our laboratory. The WXYZ ring aldehyde and the C′D′E′F′ diol were combined through the construction of the B′ ring via ringclosing metathesis and the A′ ring via O,S-acetal formation followed by radical reduction. Introduction of a terminal olefin in the side chain culminated in the convergent synthesis of the WXYZA′B′C′D′E′F′ ring segment in 16 steps.