Enantioselective synthesis of the oxadecalin core of phomactin A via a highly stereoselective Diels-Alder reaction.

Phomactin A (1) is a selective antagonist of platelet activating factor (PAF). Herein, we report our progress toward the construction of the oxadecalin core of 1. This route is based on the Diels-Alder cycloaddition of an appropriately functionalized vinyl pyran and a complementary dienophile. A model of this reaction involving 2 and maleic anhydride was conducted. Adduct 3 contains the correct stereochemical arrangements between functional groups necessary for gaining access to phomactin A. Reaction: see text.