Total Synthesis and Reconfirmation of the Absolute Configuration of (3<i>R</i>,4<i>S</i>)‑6-Acetyl-3-hydroxy-7-methoxy-2,2-dimethylchroman-4-yl(<i>Z</i>)‑2-methylbut-2-enoate Isolated from <i>Ageratina grandifolia</i>

Herein, we report the first total synthesis and confirmation of the absolute stereochemical configuration of a natural product isolated from Ageratina grandifolia as (3R,4S)-6-acetyl-3-hydroxy-7-methoxy-2,2-dimethylchroman-4-yl(Z)-2-methylbut-2-enoate. We have used readily available resorcinol as a starting material and well-established Jacobson’s asymmetric epoxidation in achieving the total synthesis. During this process, we prepared its enantiomers and positional isomers, which may be useful for biological studies.