Studies on Sesquiterpenoids. II. Absolute Configuration of Guaiol. (2). Absolute Configuration of the Methyl Group at C-10 in Guaiol, and of Nepetalinic Acids and Iridolactones.

Abstract

Since S-(+)-2-methylglutaric acid (V) and S-(-)-4-hydroxyvaleric γ-lactone were obtained by degradation of an α, β-unsaturated ketone (II) derived from guaiol (I), the configurations of the methyl groups at C-4 and C-10 in guaiol are both α-oriented and guaiol should be represented by (XII). Further, from these results the stereochemistry of four isomeric nepetalinic acids and iridolactones was elucidated.