Diastereoselective syntheses of 2-amino propargyl alcohols. Chiral building blocks for enantiopure amino γ-lactones and 5-hydroxy-piperidinone derivatives

α-Dibenzylamino aldehydes, derived from the corresponding natural α-amino acids, react with metal acetylides to yield anti-amino propargyl alcohols in good yield and diastereomeric excess. syn Amino alcohols are prepared from the anti diastereoisomers and all of them are elaborated in few steps to enantiopure amino lactones and hydroxy-piperidin-2-ones.