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 dino-flagellate Gambierdiscus toxicus, was achieved based on a convergent strategy via a-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 ring-closing 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.