Total Synthesis of (R)-(+)-Kavain via (MeCN)2PdCl2-Catalyzed Isomerization of a cis Double Bond and Sonochemical Blaise Reaction

From the chiral source 2,3-O-isopropylidene-d-glyceraldehyde 2, the natural product (R)-(+)-kavain 1a was efficiently synthesized in a total yield of 25% via (MeCN)2PdCl2-catalyzed isomerization of the cis double bond of an olefin as the key step and sonochemical Blaise reaction. The chiral center adjacent to the cis double bond was retained without protection of the free allylic hydroxy during the isomerization process.