摘要
研究了在β-环糊精存在下,苯乙酮衍生物中取代基团对不对称还原反应的影响.结果表明,当苯乙酮上连有取代基团且在低温下进行不对称还原反应时,对映体选择性得到提高,产物醇的绝对构型与取代基团的位置有关,苯乙酮及其间位、对位衍生物还原产物绝对构型为S型,邻位衍生物所得产物为R型.苯乙酮衍生物的对映体选择性是取代基团的大小、氢键作用、空间位阻等因素协同作用的结果.此外,根据取代基团的性质以及取代位置推测了底物在β-环糊精空腔内的可能定位.
Effects of substutuent groups in the presence of β-cyclodextrin on asymmetric reduction of acetophenone derivatives have been studied. The results indicated that substituent groups and low reaction temperature improved enantioselectivity for this asymmetric reaction. Absolute configuration of the resulting alcohols are depending upon the positions of substutuent groups, preponderant absolute configuration of acetophenone and its meta- and para-derivatives was the S while the prevailing absolute configuration was the R in the case of the orth-derivatives. Effects of enantioselectivity of substituted acetophenones were due to the combination of bulkiness of substituent groups, hydrogen bonding, space steric and so on. In addition, preferential orientations of the substrate included inside the β-cyclodextrin are suggested from above results.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2009年第3期277-281,共5页
Journal of Molecular Catalysis(China)
基金
湖南省自然科学基金资助项目(05JJ30024)
关键词
Β-环糊精
不对称诱导
对映体选择性
氢键
定位
β-cyclodextrin
Asymmetric induction
Enantioselectivity
Hydrogen bonding
Orientation
