B. Schmidt, O. Kunz
Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C2-symmetric building block: a strategy for the synthesis of decanolide natural products
Beilstein J. Org. Chem. 2013, 9, 2544
DOI: 10.3762/bjoc.9.289
Starting from the conveniently available ex-chiral pool building block (R,R)-hexa-1,5-diene-3,4-diol, the ten-membered ring lactones stagonolide E and curvulide A were synthesized using a bidirectional olefin-metathesis functionalization of the terminal double bonds. Key steps are (i) a site-selective cross metathesis, (ii) a highly diastereoselective extended tethered RCM to furnish a (Z,E)-configured dienyl carboxylic acid and (iii) a Ru-lipase-catalyzed dynamic kinetic resolution to establish the desired configuration at C9. Ring closure was accomplished by macrolactonization. Curvulide A was synthesized from stagonolide E through Sharpless epoxidation.
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