本文以L-异亮氨酸为手征性助剂,以甘氨酸为原料,通过(3S)-2,5-二甲氧基-3-另丁基-3,6-二氢吡嗪(5)为杂环中间体,研究了(R)-α-氨基酸的对映选择合成.在丁基锂作用下,化合物5的烷基化反应按负碳离子反应机理提供了锂衍生物(6),然后与卤代烷RX(7)作用得到具有很高立体选择性的烷基化产物(8).在反应中,7的R基因以反式于C-3位的另丁基而进入化合物8的C-6位,即在C-6位引入了(R)-构型.水解后得到了(R)-α-氨基酸甲酯(9)。 In this paper, L-isoleucine is used as a chiral adjuvant, glycine as a starting material and (3S) -2,5-dimethoxy-3-dibutyl-3,6-dihydropyrazine ) As heterocyclic intermediates, the enantioselective synthesis of (R) -α-amino acids was studied. The alkylation of compound 5 provided the lithium derivative (6) according to the carbanion mechanism under the action of butyl lithium , And then reacted with the alkyl halide RX (7) to obtain the highly stereoselective alkylated product (8). In the reaction, the R gene of 7 entered the compound 8 The (R) -configuration was introduced at the C-6 position, ie, at position C-6. The (R) -alpha-amino acid methyl ester (9) was obtained after hydrolysis.