posted on 2007-03-02, 00:00authored byYuichi Kobayashi, Shinya Yoshida, Moriteru Asano, Akira Takeuchi, Hukum P. Acharya
The 3-alkene-1,2,5-triol structure is not only a major framework of biologically important molecules but
also a new functional-group-rich unit for synthesis of polyols and sugars. A method furnishing such triol
derivatives 8 was developed and successfully applied to synthesis of decarestrictine D (18). First, coupling
reaction of the unprotected alcohols 2 with borates 4 was investigated to produce the dienyl alcohols 6
with NiCl2(dppf) in Et2O/THF (5:1) at room temperature. The hydroxyl-group-directed epoxidation of 6
followed by palladium-catalyzed reaction with AcOH (Scheme ) furnished 3-alkene-1,2,5-triol derivatives
8. Since each step proceeded with high stereo- and regioselectivities, the stereochemistry of 8 has been
correlated with the olefin geometry of 6. With the above transformation in mind, synthesis of the full
carbon skeleton of decarestrictine D (18) could be designed easily and was completed successfully.
Furthermore, a new seco acid 19b with the MOM protective group for the three hydroxyl groups was
found to afford macrolide 48 in a yield higher than those reported previously.