镍催化α-苄基溴化物与炔基铝试剂的不对称偶联反应

发布时间：2017-12-31 10:37

本文关键词：镍催化α-苄基溴化物与炔基铝试剂的不对称偶联反应　出处：《安徽师范大学》2016年硕士论文　论文类型：学位论文

【摘要】：手性炔丙基化合物由于其碳碳三键可以转换为其他官能团,是非常重要的有机合成中间体。催化不对称炔丙基取代反应和过渡金属催化C-C键的不对称偶联是合成手性炔丙基化合物的最常见方法。本文研究过渡金属镍催化α-苄基溴化物与(杂)芳香炔基铝试剂的不对称偶联来合成手性炔丙基化合物。首先,我们筛选不同的催化剂和手性配体,发现10 mol%NiBr_2(diglyme)搭配12 mol%的(R)-iPr-Pybox配体能催化合成89%产率和82%ee的苯炔丙基化物,在此最优的条件下,对底物的适应性进行了拓展,发现其有较为宽阔的适用范围。研究发现,取代基的电子效应和立体效应对反应体系有一定的影响:具有供电子基团的炔基铝试剂和芳香溴代物均能提高反应的产率,而含吸电子基团的炔基铝试剂或溴代物参与反应所得产率均不同程度有所降低;原料中的位阻效应对反应产率的影响不是很大。另外,铝试剂和溴代物中供电子基团对反应的立体选择性均有促进作用,而吸电子基团则存在一定的阻碍作用,位阻效应则会降低反应的立体选择性。总之,在NiBr_2(diglyme)/(R)-iPr-Pybox的催化下,芳香炔基铝试剂与α-苄基溴化物能快速高立体选择性的进行不对称偶联,并且具有宽广的底物拓展性。
[Abstract]:Chiral propargyl compounds because of its carbon carbon triple bond can be converted into other functional groups, is a very important organic synthesis intermediate. Is the most common method of synthesis of chiral propargyl compounds catalyzed asymmetric propargyl substituted asymmetric coupling reaction and transition metal catalyzed C-C bond. This paper studies the transition metal catalyzed by nickel alpha benzyl bromide and (Miscellaneous) the asymmetric coupling of aromatic alkynyl Aluminum Reagent to synthesize chiral propargyl compounds. Firstly, we screened different catalysts and chiral ligands, 10 mol%NiBr_2 (diglyme) mol% (R) 12 collocation -iPr-Pybox ligands benzene Propargylation catalyzed synthesis of 89% yield and 82%ee, under the optimal conditions, the substrate adaptability is developed, the application range is wide. The study found that the electronic effects of substituents and steric effects have certain effects on the reaction system for: Alkynyl Aluminum Reagent and aromatic bromides with electron donating groups can improve the yield of the reaction, while containing electron withdrawing groups of alkynyl bromides or aluminum reagent in the reaction the yield decreased in different degree; influence of steric effect on the yield of raw material is not great. In addition, the aluminum reagent and bromide in the donor group were on stereoselective catalysis and electron withdrawing groups have certain negative effects, steric effect will reduce the stereoselectivity. In short, the NiBr_2 (diglyme) / (R) -iPr-Pybox catalysts, aromatic alkynyl Aluminum Reagent and alpha benzyl bromide can fast and high stereoselectivity of asymmetric coupling, and has broad substrate expansion.

【学位授予单位】：安徽师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O621.251

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