A new class of natural products called isoprostanes are formed in huma
ns as a result of non-enzymatic free-radical-catalyzed lipid peroxidat
ion. Isoprostanes possess biological activity and can be used as an in
dex of free-radical lipid peroxidation and as a marker of oxidative st
ress. We report here a new and general synthetic methodology for the s
yntheses of isoprostanes, using the four key lactones which are constr
ucted from D-and L-glucose by a thionocarbonate-mediated radical cycli
zation reaction. These lactones possess the required stereochemistry a
nd the right functional groups for the syntheses of isoprostanes.