<b>A Catalytic Asymmetric Synthesis of </b><b><i>N</i></b>-Boc-β-Methylphenylalanines
作者:Mireia Pastó、Albert Moyano、Miquel A. Pericàs、Antoni Riera
DOI:10.1021/jo971178f
日期:1997.11.1
enantioselective synthesis of the syn and anti diastereomers of N-Boc-beta-methylphenylalanine has been developed. Starting from enantiomerically pure (2S,3S)-2,3-epoxy-3-phenyl-1-propanol, a three-step sequence, consisting of the oxidation of the primary alcohol up to the carboxyl stage, ring opening of the epoxy acid with Me(2)CuCNLi(2), and esterification of the resulting hydroxy acid with methyl iodide
已经开发了N-Boc-β-甲基苯基丙氨酸的顺式和反式非对映异构体的有效,立体发散和对映选择性的合成。从对映体纯的(2S,3S)-2,3-环氧-3-苯基-1-丙醇开始,分三步进行,包括将伯醇氧化至羧基阶段,环氧酸的开环与Me(2)CuCNLi(2)并用甲基碘将生成的羟基酸酯化,可得到羟基酯抗10,它已以立体发散的方式转化为(2S,3R)和(2R N-Boc-β-甲基苯基丙氨酸的,3R)非对映异构体分别是syn-1和anti-1。将抗10的仲羟基活化为甲磺酸酯,然后用叠氮化钠进行亲核置换,氢解反应同时保护氨基,并用LiOH皂化,得到syn-1。依次通过抗10与对硝基苯甲酸的Mitsunobu反应获得,然后水解所得的对硝基苯甲酸酯水解而获得的,适用于syn-10的相同反应序列导致抗-1。两种产物均以> / = 99%的对映体过量获得。