Expanded Helicenes as Synthons for Chiral Macrocyclic Nanocarbons
Expanded Helicenes as Synthons for Chiral Macrocyclic Nanocarbons
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DOI：
10.1021/jacs.0c03177
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发表时间：
2020-06-24
影响因子：
15
通讯作者：
Tilley, T. Don
中科院分区：
文献类型：
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作者：
Kiel, Gavin R.;Bay, Katherine L.;Tilley, T. Don
膨胀的螺旋烯是大的、结构灵活的π-框架，其可以被视为更复杂的手性纳米碳的结构单元。在这里，我们报告了一个克级合成的炔官能化的扩展的[11]螺烯和它的一步转化成两种结构和功能不同类型的大环衍生物：（1）8字形二聚体通过炔复分解（也克级）和（2）两个亚芳基桥接的扩展螺烯通过Zr介导的，正式的[2+2+n]环加成。亚苯基桥连的螺烯显示出比其螺烯前体高得多的对映异构化势垒（22.1千卡/摩尔）（
Expanded helicenes are large, structurally flexible pi-frameworks that can be viewed as building blocks for more complex chiral nanocarbons. Here we report a gram-scale synthesis of an alkyne-functionalized expanded [11]helicene and its single-step transformation into two structurally and functionally distinct types of macrocyclic derivatives: (1) a figure-eight dimer via alkyne metathesis (also gram scale) and (2) two arylene-bridged expanded helicenes via Zr-mediated, formal [2+2+n] cycloadditions. The phenylene-bridged helicene displays a substantially higher enantiomerization barrier (22.1 kcal/mol) than its helicene precursor (