Diastereoselective syntheses of 2-amino propargyl alcohols. Chiral building blocks for enantiopure amino γ-lactones and 5-hydroxy-piperidinone derivatives
摘要:
alpha-Dibenzylamino aldehydes, derived from the corresponding natural alpha-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 diastereo-isomers and all of them are elaborated in few steps to enantiopure amino lactones and hydroxy-piperidin-2-ones. (c) 2006 Elsevier Ltd. All rights reserved.
AsymmetricvinylogousMannichreaction (VMR) of 2-(tert-butyldimethylsilyloxy)furan (TBSOF, 1) with (RS)- or (SS)-t-BS-imines (3) furnished 5-aminoalkylbutenolides 7a–k in 75–87% yields with anti/syn ratios ranging from 75:25 to 97:3. Butenolides 7a–f,k were readily converted into substituted lactones 8 and 5 and 6-substituted 5-hydroxypiperidin-2-ones 11a–g, which are, in turn, key intermediates for