SYNTHESIS OF EXO-6,7-EPOXYTROPANE AND ENDO-6,7-EPOXYTROPANE

Diastereoisomeric N-protected 2,3-epoxy-4-amino-cycloheptanols are syn thesised: cyclisation of derivatives provides a practical route to N-p rotected exo-(beta-)-6,7-epoxynortropanes and the first endo-(alpha-)- 6.7-epoxynortropane. Hydride reduction gives the corresponding exo- an d endo- 6-hydroxytropanes respectively. However, the exo-epoxide survi ves both hydride treatment at low temperature and hydrogenolysis, allo wing retention of the epoxide during conversion of the benzyloxycarbon yl group respectively into N-methyl or NH derivatives thus opening an effective route to exo-6,7-epoxytropanes and -nortropanes. The N-prote cted 1-hydroxy-6,7-epoxytropane analogues actually exist as the monocy clic 2,3-epoxy-4-aminocycloheptanone tautomers. Copyright (C) 1996 Els evier Science Ltd.