Synthesis of pyragonicin.

[structure: see text] A stereocontrolled convergent synthesis of the annonaceous acetogenin pyragonicin (1) is presented. The key intermediates were accessed using asymmetric Horner-Wadsworth-Emmons (HWE) methodology. A reagent controlled zinc-mediated stereoselective coupling, joining the two highly functionalized intermediates 3 and 4, then provided the core structure.