DIASTEREOSELECTIVE AND REGIOSELECTIVE SYNTHESIS OF DIQUINANES AND RELATED SYSTEMS FROM TRICYCLO[3.3.0.0(2,4)]OCTANES BY CHEMICAL ELECTRON-TRANSFER (CET)

A new synthetic methodology for diquinanes by one-electron oxidation o f tricyclo[3.3.0.0(2,4)]octanes and subsequent stereocontrolled rearra ngement is provided. The latter compounds are conveniently accessible through acid-catalyzed isopyrazole cycloaddition, followed by hydrogen ation and photoextrusion of molecular nitrogen. The oxidative rearrang ement of the tricyclooctanes proceeds catalytically and cleanly to aff ord regio- and diastereoselectively the corresponding diquinanes.