晶体结构,计算研究和赫什菲尔德对1,2,3,5-四-1a',9b'-di-hydro-spiro-[bi-cyclo-[3.1.0]hexane-6,1'-cyclo-propa[phenanthren]-2-en-4-one的分析
Alexander D Roth1, Dasan M Thamattoor1
1Department of Chemistry Colby College,Waterville ME 04901 USA.
概括
双诺二烯与四环二烯的反应产生了一个拥挤的螺旋二烯与外立体化学,与之前的内分产品形成对比. 过渡状态中的固体相互作用有利于外异构体,尽管其热力学稳定性较低.
科学领域:
- 有机化学 有机化学
- 立体化学是一种立体化学.
- 晶体学 晶体学是指结晶学.
背景情况:
- 之前的研究报告了二子和子的反应中的内分立体化学反应.
- 螺旋坦 adducts 以其无菌拥堵而闻名.
研究的目的:
- 为了研究二松和四环丁之间的反应的立体化学结果.
- 为了确定由此产生的螺旋坦 adduct 的结构.
- 阐明影响这种反应中的立体选择性的因素.
主要方法:
- 使用X射线结晶学来确定产品的精确立体化学.
- 密度函数理论 (DFT) 计算 (DLPNO-CCSD(T) /def2-TZVP//B3LYP/def2-SVP) 用于评估二聚体体的相对能量.
- 从/乙酸乙烯的结晶被用来获得用于分析的单晶.
主要成果:
- 反应产生了一个高度拥挤的螺旋坦与外立体化学,由X射线结晶学证实.
- 四环二胺添加物结晶在单临床系统中,空间组P21/n.
- 计算研究表明,这两种内分异构体在热力学上比各自的外分异构体更稳定.
结论:
- 观察到的外体立体化学是由于过渡状态中的破坏稳定的硬体相互作用引起的,有利于不太稳定的外体异构体而不是内体异构体.
- 环旋转在四cyclopentadienone组件中,在决定立体化学结果方面起着至关重要的作用.
- 这项研究突出了热力学和动力学之间的复杂相互作用,用于控制在硬质要求较高的反应中的立体选择性.
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