862425-11-4Relevant academic research and scientific papers
Diastereo- And enantioselective synthesis of β-Hydroxy-α-amino acids: Application to the synthesis of a key intermediate for lactacystin
Li, Qiong,Yang, Shao-Bo,Zhang, Zhihui,Li, Lei,Xu, Peng-Fei
supporting information; experimental part, p. 1627 - 1631 (2009/09/24)
The development of a highly efficient and stereoselective methodology for the preparation of β-hydroxy-α- amino acids is described. Nucleophilic addition of enolates of tricyclic iminolactones 1a and 1b to aldehydes in the presence of 6 equiv of lithium chloride in THF at -78 °C leads to aldol adducts in good yield (63-86%) and high diastereoselectivity (up to >25:1 dr). Subsequently, hydrolysis of the aldol adducts under acidic conditions leads to the corresponding β-hydroxy-a-amino acids in good yields (up to 83%) and excellent enantiomeric excesses (99% ee) with good recovery yields of the chiral auxiliaries 6 and 7. This methodology was applied to the facile synthesis of the key intermediate for lactacystin along with several isomers.
