Total Synthesis of Solandelactone I

Since the marine natural products solandelactones A-I were isolated from the hydroid Solanderia secunda and investigated by Seo et al. in 1996, considerable synthetic efforts toward these marine oxylipins followed. However, the structure elucidation of solandelactone I remained incomplete, and no synthesis has been reported. On the basis of our retrosynthetic analysis, the key building blocks were combined in a Horner-Wadsworth-Emmons reaction to create two common intermediates for the stereodivergent synthesis of all four diastereomers 1-4 matching the proposed structure of solandelactone I. Comparison of the published analytical data of natural product solandelactone I and data obtained from the synthetic endeavor toward diastereomers 1-4 enabled the structure assignment of isomer 3; the proposed biosynthetic pathway for marine oxylipins also supports the result.