The functionalized N-alkyl-β-enaminoesters 11 are precursors of nitrogen-bridged bicyclic β- enaminoesters 7. The compounds 7 are prepared either by intramolecular alkylation of β- enaminoesters 11 or by thermolysis of β-enaminoesters 6. A stereospecific reduction of compounds 7 under thermal control leads to bicyclic β-aminoesters 13, 14, 15 or 16 which are good precursors of natural aminoalcohols like lupinine 4 or isoretronecanol 2.