摘要:
The novel, chiral glycinamides (S,S)-3 and (S,S)-4 were prepared in good yields from C-2-symmetric chiral amines (S,S)-1 and (S,S)-2, respectively. Enolate formation and addition to methyl iodide and benzyl bromide proceeded in good yield and high diastereoselectivity, especially in the presence of LiCl or DMPU. Removal of the phthaloyl protecting group with hydrazine, followed by hydrolysis with 6N HCl, converted the benzylated product (S,S,S)-7 to enantiopure (S)-phenylalanine. (C) 2000 Elsevier Science Ltd. All rights reserved.