A Simple Synthesis of α,β-Unsaturated γ-Aminobutyric Acid (GABA) Derivatives from Enamines
作者:Hans Henniges、Chiara Gussetti、Hans-Christian Militzer、Mark S. Baird、Armin de Meijere
DOI:10.1055/s-1994-25716
日期:——
Bromination of enamines 3b-g at - 78°C and subsequent treatment of the resulting iminium salts 4b-g with excess tert-butyl lithioacetate leads to tert-butyl 4-(N,N-dialkylamino)carboxylates 9b-g in good to very good yields. Ester cleavage of the dibenzylamino derivative 9d with trifluoroacetic acid yields the corresponding acid 10. Subsequent catalytic hydrogenation of 10 leads to the fully deprotected 4-amino-4-methylpentanoic acid (12) in high yield.
在-78°C下对烯胺3b-g进行溴化反应,随后用过量的叔丁基锂乙酸酯处理生成的亚胺盐4b-g,可以得到收率良好至非常好的叔丁基4-(N,N-二烷基氨基)羧酸酯9b-g。用三氟乙酸裂解二苄胺衍生物9d的酯,得到相应的酸10。接着对10进行催化氢化反应,可以高收率地得到完全脱保护的4-氨基-4-甲基戊酸(12)。