The diazo ketone approach to the isoprostanes.

A general synthetic approach to the isoprostanes has been established, based on intermolecular aldol condensation of a diazo ketone with an unsaturated aldehyde, followed by cyclization of the resulting diazo ketone to the cyclopropane. Subsequent kinetic opening with thiophenol followed by further elaboration then leads to the isoprostane. The history of this approach and the details of its development are discussed.

Diastereoselective Synthesis of an Isoprostane: (+/-)-8-epi-PGF(2)(alpha) Ethyl Ester.

A total synthesis of the isoprostane (+/-)-8-epi-PGF(2)(alpha) ethyl ester (5) is described, based on the diastereoselective cyclization of alpha-diazo ketone 7. This ketone is assembled by aldol condensation between alpha-diazo ketone 8 and aldehyde 9. The sequential alpha-diazo ketone aldol/insertion described here offers a powerful new approach to cycloalkane construction.