No abstract

A series of (R)-N-Cbz-2-alkyl-2-amino-3-hydroxypropyl acetates was prepared by enzymatic acetylation of NCbz-2-alkyl-2-aminopropane-1,3-diols with immobilized lipoprotein lipase from Pseudomonas sp. in up to 98% enantiomeric excess (ee). Enantiodivergent oxidation of (R)-N-Cbz-2-alkyl-2-amino-3-hydroxypropyl acetates readily furnished (R)-and (S)--substituted serines ( -benzylserines and -methylserines). Enzymatic hydrolysis of diethyl N-Cbz-2-amino-2-methylmalonate catalyzed by porcine liver esterase afforded (R)-N-Cbz-2-amino-3-ethoxy-2-methyl-3-oxopropanoic acid in 97% ee. (R)-N-Cbz-2-amino-3-ethoxy-2-methyl-3-oxopropanoic acid was also transformed to both enantiomers of -methylserine via enantiodivergent reduction.

Enzymatic acetylation of several varieties of N-Cbz-2-alkyl-2-amino-1,3-propanediols 3a -d with immobilized lipoprotein lipase from Pseudomonas sp. afforded N-Cbz-3-acetoxy-2-alkyl-2-amino-1-propanols 4a -d in up to 98% ee. A facile synthesis of (R)-and (S)-α-benzylserines [(R)-and (S)-8a ] was achieved by enantiodivergent conversion of chiral N-Cbz-3-acetoxy-2-amino-2-benzyl-1-propanol (R)-4a .