STEREOSELECTIVE OXYGENATION OF THE HOMOTROPANE RING-SYSTEM - SYNTHESIS OF EXO-7-HYDROXYTROPANES AND ENDO-7-HYDROXYTROPANES AND 7,8-EPOXYHOMOTROPANES

Stereoselective introduction of an endo- epoxide into the 2-carbon bri dge of the homotropane (9-azabicyclo[4.2.1]nonane) ring system has bee n achieved via a 4-aminocyclooct-2-enol derivative; the direct route t o the exo- analogue from 7,8-dehydrohomotropanes is less efficient but the novel exo- and endo-epoxides show substantially different reactiv ity. Completely different tautomeric preferences are observed for the two diastereoisomeric 1-hydroxy-7,8-epoxyhomotropanes, unexpectedly pr oviding the method of choice for a clean and effective synthesis of th e exo-epoxyhomotropane derivatives.