Diastereo- and Enantioselective Synthesis of β-Hydroxy-α-Amino Acids: Application to the Synthesis of a Key Intermediate for Lactacystin Qiong Li Shao-Bo Yang Zhihui Zhang Lei Li Peng-Fei Xu 10.1021/jo8023973.s001 https://acs.figshare.com/articles/journal_contribution/Diastereo_and_Enantioselective_Synthesis_of_Hydroxy_Amino_Acids_Application_to_the_Synthesis_of_a_Key_Intermediate_for_Lactacystin/2876989 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 <b>1a</b> and <b>1b</b> 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-α-amino acids in good yields (up to 83%) and excellent enantiomeric excesses (99% ee) with good recovery yields of the chiral auxiliaries <b>6</b> and <b>7</b>. This methodology was applied to the facile synthesis of the key intermediate for lactacystin along with several isomers. 2009-02-20 00:00:00 Enantioselective Diastereo stereoselective excess diastereoselectivity Application Intermediate acid lithium enolate hydrolysis Lactacystin lactacystin recovery dr presence methodology enantiomeric equiv chloride Synthesi Nucleophilic aldehyde 7. ee acidic THF aldol adducts Hydroxy auxiliary tricyclic iminolactones 1 chiral auxiliaries 6 yield preparation isomers synthesis Acid hydroxy