Asymmetric Synthesis of α-Methyl α-Amino Acids through Diastereoselective Alkylation under Mild Reaction Conditions of an Iminic Alanine Template with a 1,2,3,6-Tetrahydro-2-pyrazinone Structure
作者:Carmen Nájera、Tomás Abellán、José M. Sansano
DOI:10.1002/1099-0690(200008)2000:15<2809::aid-ejoc2809>3.0.co;2-x
日期:2000.8
room temperature by: a) activated alkyl halides under solid-liquid PTC conditions, b) non-activated alkyl halides with organic bases, c) electrophilic olefins employing both solid−liquid PTC conditions and organic bases, and d) allylic carbonates by means of palladium catalysis under neutral conditions. Enantiomerically pure (S)-α-methyl α-amino acids 8 are obtained by hydrolysis of the alkylated pyrazinones
从(R)-缬氨酸和(S)-丙氨酸获得的(6 R)-6-异丙基-3-甲基-5-苯基-1,2,3,6-四氢-2-吡嗪酮在以下位置高度非对映选择性烷基化室温:a)在固液PTC条件下的活化烷基卤化物; b)具有有机碱的非活化烷基卤化物; c)在固液PTC条件和有机碱下均具有亲电性的烯烃; d)通过以下方式得到烯丙基碳酸酯:钯在中性条件下催化。对映体纯的(S)-α-甲基α-氨基酸8是通过烷基化的吡嗪酮的水解得到的。