Titanium-mediated diastereoselective formation of (Z)-1-(1-alkenyl)-2-substituted-cyclopropyl eaters efficient precursors of (Z)-2,3-methanoamino acids

The titanium-mediated cyclopropanation of homoallyl alk-2-enoates, emerged as the most convenient method to form diastereomerically pure (Z)-1-(1-alke nyl)-2-alkylcyclopropanols, precursors of significant 1,1-dimethyleneallylm etal species. Then, azidation of such complexes followed by a simple reduct ion-oxidation sequence provided diastereochemically pure (Z)-2,3-methanoami no acids.