兰州大学机构库 >生命科学学院
钝化的格氏试剂对醛的不对称加成反应研究
Alternative TitleStudy On Asymmetric Addition Of Deactived Grignard Reagent To Aldehyde
尹晓刚
Thesis Advisor达朝山
2008-05-26
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword格氏试剂 不对称加成 钝化
Abstract格氏试剂是最重要和最常用的有机金属试剂之一,使用格氏试剂对双键加成是生成碳碳键的重要方法之一。不对称催化格氏试剂对醛加成可以生成多种有生物活性的手性仲醇,但是由于格氏试剂自身活性较高,其对醛不对称加成的报道也比较少。 格氏试剂对醛的不对称加成的报道大多需要大量的手性助剂以获得高的光学活性,而高度催化的格氏试剂对醛的不对称加成主要通过两种途径进行:一种是把格氏试剂转化成其他的有机金属试剂,如二烷基锌化合物或烷基钛化合物再对醛进行加成,反应通常在低温下进行;另一种是利用手性镁胺作为中间体或直接用手性胺催化来完成此反应。 我们通过利用异丙醇钛和双(二甲胺基乙基)醚在冰水条件下协同作用,成功的降低了格氏试剂对醛加成的反应活性。研究显示,BINOL,异丙醇钛,格氏试剂的量等条件对立体选择性有很大影响,在最优条件下,不同格氏试剂对苯甲醛加成可以得到中等到优秀的立体选择性产物。其中,异丁基格氏试剂加成产物ee值最高,为98%,同样条件下,异丁基格氏对多种取代芳香醛加成也取得很好的结果:产物ee值最低为97%,最高大于99%。
Other AbstractGrignard reagents are among the most important and traditional organometal reagents.Addition of Grignard reagents to double bond is one of most reliable methods for forming Carbon-Carbon bonds . Catalytic asymmetric addition of Grignard reagents to aldehydes can produce numerous chiral sec-alcohols, many of them have different biologically activities. However, there are few success report on asymmetric alkylation by Grignard reagents due to the intrinsic high reactivities of Grignard reagents to carbonyl compounds. For a very long time, many research groups focus on using more than a stoichiometric amount of a chiral auxiliaries to obtain high enantioselectivity. There were mainly two sorts of processes be reported on highly catalytic asymmetric addition of Grignard reagents to aldehydes. The former case was transferred Grignard reagent RMgX into other organometal reagents such as R2Zn or R-Ti derivatives via complicated procedures at extremely low temperature . The later case was directly linking a chiral ligand to Mg in the form of organomagnesium amides or use chilral amine ligand catalysis the alkylation of aldehydes. We reduced the activities of Grignard reagents successfully by complexing with Ti(OiPr) 4 and bis[2-(N,N-dimethylamino)ethyl] ether (BDMAEE) in ice-water temperature. The amount of (S)-BINOL, Ti(OiPr)4 and RMgBr have great effects on the enantioselection. Under the optimized reaction condition, moderate to good enantioselectivities in the alkylation of aldehydes were achieved. i-BuMgBr was the best one and its enantioselection was up to 98%. Under these conditions,varieties of aryl aldehydes were used to test this reaction, and their enantioselections were all over 97% and the highest two samples were over 99%.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/221523
Collection生命科学学院
Recommended Citation
GB/T 7714
尹晓刚. 钝化的格氏试剂对醛的不对称加成反应研究[D]. 兰州. 兰州大学,2008.
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