Synthesis of the C'D'E'F' domain of maitotoxin.

A devised biomimetic strategy toward the C'D'E'F' domain (6) of maitotoxin (1) led to hydroxy triepoxide 8 as a postulated polyepoxide precursor. However, all attempts to induce the desired cascade to form the targeted compound through a zip-type reaction under neutral or acidic conditions failed, prompting adoption of a linear stepwise approach to 6. The successful synthetic strategy for the synthesis of the C'D'E'F' domain of maitotoxin commenced from furfuryl alcohol (11), proceeded through F' ring building block 15, and involved two regio- and stereoselective intramolecular hydroxy epoxide openings and a stereoselective SmI(2)-mediated ring closure to forge rings C', E', and D', respectively. (13)C NMR spectroscopic analysis of the synthesized domain (6) and comparisons with previous results confirmed the original structural assignment of this region of maitotoxin. X-ray crystallographic analysis of 6 provided unambiguous proof of its structure.