ENANTIOSPECIFIC AND DIASTEREOSELECTIVE SYNTHESIS OF ANTI-ALPHA-HYDRAZINO-BETA-HYDROXYACIDS AND ALPHA-AMINO-BETA-HYDROXYACIDS THROUGH ELECTROPHILIC AMINATION OF BETA-HYDROXYESTERS
ENANTIOSPECIFIC AND DIASTEREOSELECTIVE SYNTHESIS OF ANTI-ALPHA-HYDRAZINO-BETA-HYDROXYACIDS AND ALPHA-AMINO-BETA-HYDROXYACIDS THROUGH ELECTROPHILIC AMINATION OF BETA-HYDROXYESTERS
复制标题
DOI：
10.1016/s0040-4020(01)86060-9
复制
发表时间：
1988-01-01
期刊：
影响因子：
2.1
通讯作者：
NARISANO, E
中科院分区：
文献类型：
--
作者：
GUANTI, G;BANFI, L;NARISANO, E
度量。将-羟基酯1 -d转化为相应的双离子，与二叔丁基二羧酸酯缩合得到抗保护的- α -肼- β。-羟基酯2 - a-d具有良好的非对映选择性（高达94:6）。保护基团的裂解和酯水解产生了以前未知的抗- -肼基- -。-羟基酸4a-d，通过氢解转化为抗- α -氨基- β。-hydroxyacids 5模拟。从(S) 1a开始，获得了对映体纯的（2S, 3S）异位苏氨酸5a，总产率较高。与此相反，由1a衍生的硅烯酮缩醛10与重氮盐的反应主要产生了同分异构体，但产率不理想。
.beta.-Hydroxyesters 1a-d were transformed into corresponding dianions and condensed with di-t-butylazodicarboxylate to give anti proteced .alpha.-hydrazino-.beta.-hydroxyesters 2a-d with good diastereoselectivities (up to 94:6). Cleavage of protecting groups followed by ester hydrolysis gave the previously unknown anti .alpha.-hydrazino-.beta.-hydroxyacids 4a-d, which were in turn converted by hydrogenolysis into anti .alpha.-amino-.beta.-hydroxyacids 5a-d. Starting from (S) 1a, enantiomerically pure (2S, 3S) allo-threonine 5a was obtained in good overall yields. On the contrary, reaction of silyl ketene acetal 10, derived fom 1a, with a diazonium salt furnished predominantly the syn isomer, but in unsatisfactory yield.