Enantioselective Synthesis of (−)-Terpestacin and Structural Revision of Siccanol Using Catalytic Stereoselective Fragment Couplings and Macrocyclizations
A practical synthesis of 10'R-acetoxy-11'-hydroxyumbelliprenin was achieved using regioselective Sharpless asymmetric dihydroxylation as a key reaction, in which the regioselectivity was achieved by using (DHQD)(2)AQN as a ligand instead of the conventional (DHQD)(2)PHAL. 10'R-Acetoxy-11'-hydroxyumbelliprenin was synthesized by the coupling of a coumarin unit (umbelliferone) and sesquiterpene unit in 11% overall yield through 5 steps.