A Large-Scale Preparation of (3S, 4S)-3-(tert-Butoxycarbonyl) amino-4-methylpyrrolidine and Its Analogs from L-Aspartic Acid.

T YOSHIDA, M TAKESHITA, H ORITA…

Index: Yoshida, Toshihiko; Takeshita, Makoto; Orita, Hitomi; Kado, Noriyuki; Yasuda, Shingo; Kato, Hideo; Itoh, Yasuo Chemical and Pharmaceutical Bulletin, 1996 , vol. 44, # 5 p. 1128 - 1131

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Citation Number: 6

Abstract

(3S, 4S)-3-(tert-Butoxycarbonyl) amino-4-methylpyrrolidine (12a) was synthesized from L- aspartic acid (4) on a large scale. Methylation of dimethyl (2S)-N-benzyl-N-(9-phenylfluoren- 9-yl) aspartate (5), easily derived from 4, with methyl iodide gave (3R)-3-methylaspartate (6a) in 91% yield with high diastereoselectivity. Reduction of 6a with lithium aluminum hydride, followed by hydrogenolysis, protection with di-tert-butyl dicarbonate, and ...