The bungeanools are a family of alkamide natural products isolated from the pericarps of Zanthoxylum bungeanum (Sichuan pepper), and they are structurally related to the sanshools. While the sanshools, especially hydroxy-α-sanshool, have been studied in a variety of contexts, research regarding the bungeanools has been much more limited. Therefore, in order to facilitate their study we have developed stereoselective syntheses of all four members of this family of compounds using flexible routes that are amenable to the synthesis of analogues as well. The key transformation in the syntheses was the stereoselective triphenylphosphine/phenol-catalyzed isomerization of an alkynoate to the corresponding conjugated E-,E-dienoate.
