Practical Enzymatic Desymmetrization of 2-(Ethoxycarbonyl)propane-1,3-diyl Dihexanoate and Model Cyclization for the A–D Ring System of Lysergic Acid
作者:Sachiho Miyata、Takuya Kumamoto、Tsutomu Ishikawa
DOI:10.1002/hlca.200790144
日期:2007.7
symmetrical 2-(ethoxycarbonyl)propane-1,3-diyl dihexanoate, under the modified conditions of the Seebach protocol, afforded a desymmetrized monohexanoate in 40–51% yield with 91–94% ee, even in a gram-scale reaction. The absolute configuration of a half-hydrolyzed (−)-product was determined to be (R) by conversion to a known 2-methylpropane-1,3-diol derivative. Samarium iodide-induced radical cyclization
在Seebach方案的改良条件下,猪胰脂肪酶催化对称的2-(乙氧羰基)丙烷-1,3-二基二己酸酯的水解,得到了脱对称的单己酸酯,产率为40-51%,ee为91-94%,即使在克级反应。通过水解成已知的2-甲基丙烷-1,3-二醇衍生物,将半水解的(-)产物的绝对构型确定为(R)。the离子诱导的N-原子上带有C 4单元的2-氧代-3-苯基乙胺的自由基环化,由消旋单己酸酯衍生而来,提供了3-苯基哌啶衍生物,作为麦角酸A–D环系统的模型构建酸。