Ring-closing metathesis of diolefinic oxazolidinones: a new access to tropanes and aminocyclitols

Ring-closing metathesis of diolefinic oxazolidinones prepared through N-Boc-2-acyl or α,β-epoxy oxazolidine methodology give stereodefined bicyclic oxazolidinones. The 5,6-membered bicyclic oxazolidinones are then converted into new aminocyclitols by diastereoselective dihydroxylation whereas their 5,7-membered bicyclic homologues are transformed into tropanic alkaloids through an aminocyclization step.