Synthesis of potassium 2,3,4-trihydroxy-2-methylbutanoate: a leaf-closing substance of Leucaena leucocephalam
作者:Sanjib Gogoi、Narshinha P. Argade
DOI:10.1016/j.tet.2004.07.081
日期:2004.10
diesterification, OsO4-dihydroxylation, acetonide protection, regioselective mono hydrolysis of unhindered ester moiety, borane–dimethylsulfide induced chemoselective reduction of carboxylic group and hydrolysis pathway. Surprisingly, the sodium borohydride reduction of monoester 5 and lithium borohydride reduction of 11 furnished the undesired regioisomer 7.
从柠康酸酐(2)开始,已描述了一种六步合成的闭叶物质(±)-2,3,4-三羟基-2-甲基丁酸赤藓酸钾(1),通过二酯化OsO的总收率为29%4-二羟基化,丙酮化物保护,不受阻碍的酯部分的区域选择性单水解,硼烷-二甲基硫醚诱导的羧基化学选择性还原和水解途径。令人惊讶地,单酯5的硼氢化钠还原和11的硼氢化锂还原提供了不希望的区域异构体7。