作者:Marco Born、Christoph Tamm
DOI:10.1002/hlca.19900730821
日期:1990.12.12
The synthesis of diester 3, a synthon for the C(19)-to-C(27) segment of rifamycin S (1), is described, starting from the meso-diester 4 (Schemes 2 and 3). Inversion of the configuration at the later C(23) and two aldol condensations with the lithium enolate 18 of 2,6-dimethylphenyl propionate each producing two new chiral centres of threo-configuration, led to the desired diester 3. The absolute configuration
描述了二酯3的合成,它是利福霉素S(1)从C(19)到C(27)片段的合成子,从内消旋二酯4开始(方案2和3)。后来的C(23)的构型反转和与2,6-二甲基苯基丙酸酯的烯醇锂18的两个醛醇缩合反应各自产生两个新的苏氨酸构型手性中心,从而产生了所需的二酯3。新的手性中心的绝对构型已通过中间体19的单次X射线分析(图)和转化二酯3得以证明。进入中消旋体25。