Enantioselective Syntheses of Isoaltholactone, 3-epi-Altholactone, and 5-Hydroxygoniothalamin
摘要:
GRAPHICSA flexible enantioselective route to highly functionalized alpha,beta-unsaturated delta-lactones has allowed for the syntheses of the styryllactones: isoaltholactone, 3-epi-altholactone, and 5-hydroxygoniothalamin in 10%, 5%, and 13% overall yields from furfural, respectively. This approach derives its asymmetry by applying the Sharpless catalytic asymmetric dihydroxylation to vinylfuran. The resulting diols are produced in high enantioexcess and can be stereoselectively transformed into alpha,beta-unsaturated delta-lactones via a short highly diastereoselective oxidation and reduction sequence.
We have designed a convergent path for the synthesis of the key fragments (C1–C7 and C6–C22) of phostriecin. The approach not only provides ready access to several biologically active molecules, such as 5‐hydroxygoniothalamin, 5‐acetoxygoniothalamin, and their analogues, but also (S)‐5‐[(S)‐1‐hydroxyallyl]furan‐2(5H)‐one derivatives with cross metathesis as the key reaction.
Abstract The totalsynthesis of 5-hydroxygoniothalamin is achieved from commercially available l-xylose. The α,β-unsaturated-δ-lactone core is constructed in very good yield by utilizing one-carbon and two-carbon cis-Wittig olefinations and δ-lactonization using Yamaguchi conditions. Subsequent Grubbs cross-metathesis followed by desilylation results in 5-hydroxygoniothalamin. The totalsynthesis of 5-hydroxygoniothalamin