Asymmetric Synthesis and CD Investigation of the 1,4-Benzodioxane Lignans Eusiderins A, B, C, G, L, and M

摘要

The enantioselective synthesis of (−)-eusiderinsnA (1), B (2), G (25), L (23), M (5) and (+)-eusiderin Cn(20) and a range of analogues was undertaken using annefficient, divergent synthesis all from a single chiral aldehyden15, which was derived from (S)-ethyl lactate 9. Ancomprehensive set of NMR data along with ECD spectranand optical rotation measurements of the synthesized naturalnproducts and analogues were then obtained. This datanconfirmed the absolute stereochemistry of eusiderins A (1)nand C (20) and for the first time gives the ECD and opticalnrotation for eusiderins B (2), G (25), L (23), and M (5) and anrange of other substituted 1,4-benzodioxanes. This data willnnow allow for the determination of absolute stereochemistry ofnother members in this class of compound.