1.
Chirality
; 14(2-3): 144-50, 2002.
Artigo
em Inglês
| MEDLINE
| ID: mdl-11835557
RESUMO
Chiral hydantoin (S)-1 was prepared in good yield from phenyl isocyanate and N-[(S)-alpha-phenylethyl]glycinate, (S)-3. Enolate (S)-1-Li was methylated in high yield and good diastereoselectivity. In contrast, a second alkylation reaction of methylated enolate (S)-4-Li proceeded with essentially no diastereoselectivity. Nevertheless, dialkylated hydantoins, (S,S)-7 and (S,R)-7, could be readily separated by flash chromatography and subsequent hydrolysis of either derivative afforded the desired (S)-L-alpha-methyldopa or (R)-D-alpha-methyldopa in good yield.