A Concise Synthesis of Pawhuskin A

Abstract

Pawhuskin A is an isoprenylated stilbene that was isolated from Dalea purpurea and reported to have affinity for the opioid receptor in vitro. It has been synthesized through a convergent sequence that joins a prenylated aldehyde with a geranylated phosphonate in a stereoselective Horner-Wadsworth-Emmons condensation to afford the target E olefin isomer. This synthesis confirms the structure assigned to the natural product and establishes a route that may be used to explore its biological activity and to prepare more active analogues.