oxidative Polycyclization versus the 'Polyepoxide Cascade': New Pathways in Polyether (Bio) synthesis?

摘要

In 1983, Cane et al. postalated that polyether biosynthesis takes place as a two-step process. The first of these steps was proposed to be the enzymatic polyepoxidation of an acyclic hydroxypolyene precursor, and the second comprised a cascade of intramolecular epoxide ring openings with formation of the polyther framework. For monensin A (3), for exarnple this is shown in the following scheme (Scheme1): the (E, E, E)-triene 1 is transformed biosynthetically into the tris-epoxide 2, which reacts further in a cascade of epoxide ring openings to yield the natural product 3.