羧基官能化己内酯的合成

以2 乙酸乙酯环己酮为起始原料，首先将原料水解为2 乙酸环己酮，然后分别用对位带吸电子基团硝基、推电子基团甲基和无取代基的苄基保护羧基，通过拜耳 维立格氧化反应的选择性同时得到2号位或6号位带羧基保护基的己内酯同分异构体化合物，最后使用急骤层析法分离同分异构体得到高纯度的6号位羧基官能化己内酯。保护基上取代基电子效应的不同导致生成不同比率的2号位和6号位产物，带有推电子基团时生成6号位单体的比率最大。取代基的极性差异也会影响同分异构体分离的难易程度，同分异构体的极性差距越大越容易分离。

Synthesis of Carboxyl Functionalized Caprolactone

As a raw material, 2 oxocyclohexaneacetate was hydrolyzed into 2 cyclohexaneacetate. Then its carboxyl groups were protected by substituted benzyls with substituent groups including electron withdrawing group nitro, electron donating group methyl and comparative group hydrogen on the para side of benzyl. By Baeyer Villiger oxidation, 2 or 6 carboxyl functionalized polycaprolactones were generated at the same time. Afterwards, the isomers were isolated and purified using flash chromatography to obtain 6 carboxyl functionalized polycaprolactone with high purity. The electronic effect of substituent groups on the protecting groups led to the formation of isomers in different rations. A maximum rate of 6 substituted compound was obtained with the existence of electron donating group. Moreover, the difference in polarity of substituent groups affected the separation of isomers. Larger difference in polarity resulted in an easier separation.