Straightforward and Facile Synthesis of a Bioactive Component from Zingiber cassumunar Roxb.

Straightforward and facile synthesis of a bioactive component A from Zingiber cassumunarRoxb. is described. The phenylbutenoid dimer A was reported to possess anti-inflammatory and cytotoxic activities. The optically active cyclohexene ring fragment was obtained via the highly diastereo- and enantioselective Diels–Alder reaction of chiral acryloyloxazolidinones (1a and 1b) and 1-(4-hydroxy-3-methoxyphenyl)butadiene (2). The enantiomeric excess of Diels–Alder adducts 3a and 3bwere determined via high-performance liquid chromatotography of the corresponding bis-acetate (6). The greatest enantiomeric excess (99.9% ee) was obtained when the 4-phenyloxazolidin-2-one (1a) chiral auxiliary was used in combination with TiCl4. The optically pure bioactive compound A was prepared from the optically active Diels–Alder adduct (3a) in two additional steps.