 PACE=5> |
The 3-alkene-1,2,5-triol structure is not only a major framework of biologically im
portant molecules butalso a new functional-grou
p-rich unit for synthesis of
polyols and sugars. A method furnishing such triolderivatives
8 was develo
ped and successfully a
pplied to synthesis of decarestrictine D (
18). First, cou
plingreaction of the un
protected alcohols
2 with borates
4 was investigated to
produce the dienyl alcohols
6with NiCl
2(d
ppf) in Et
2O/THF (5:1) at room tem
perature. The hydroxyl-grou
p-directed e
poxidation of
6followed by
palladium-catalyzed reaction with AcOH (Scheme 1) furnished 3-alkene-1,2,5-triol derivatives
8. Since each ste
p proceeded with high stereo- and regioselectivities, the stereochemistry of
8 has beencorrelated with the olefin geometry of
6. With the above transformation in mind, synthesis of the fullcarbon skeleton of decarestrictine D (
18) could be designed easily and was com
pleted successfully.Furthermore, a new seco acid
19b with the MOM
protective grou
p for the three hydroxyl grou
ps wasfound to afford macrolide
48 in a yield higher than those re
ported
previously.
