A New Chiral Source Optically Pure 5-(1-MenthyIoxy-3, 4-dichloro-2 (5H) -furanone, Its Synthesis and Structure
Chen, Qing-Hua~* Geng, Zhe (Department of Chemistry, Beijing Normal University, Beijing, 100875)
We devised a new synthetic route to optically pure 4b based on tautomerization of the open chain to cyclic structure of mucochloric acid as well as etherification of 4-hydroxy-3, 4-dichlorobutenolide with (-)-menthol and the crystallizationinduced epimerization of γ-menthyloxy-dichlorobutenolide. 4b was identified on the basis of its elemental analytical and spectral data. The absolute configuration at the acetal carbon 5-C of 4b was proven to be S by means of a X-ray structure analysis of its tandem Michael addition-elimination reaction product with pyrrolidine.