Vinylsilane-mediated synthesis of styryl-lactone frameworks

A general route to several styryl-lactone frameworks is presented. Starting from a known enol ether, stereoselective epoxidation and methanolysis yields a series of three distinct hydroxyacetals, each further functionalized by etherification with an allylic vinylsilane fragment. A highly efficient Lewis acid-promoted intramolecular annulation at the tethered oxocarbenium allows direct entry to cis-fused bicyclic ether cores. Further manipulation delivers a variety of additional styryl-lactone motifs and analogs; for example, simple allylic oxidation yields 3-deoxyisoaltholactone, in just five steps overall.

121