MOE Laboratory of Bioinorganic and Synthetic Chemistry, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, China.
Angew Chem Int Ed Engl. 2020 May 25;59(22):8661-8669. doi: 10.1002/anie.201916722. Epub 2020 Mar 20.
Although the photodimerization of acenaphthylene (ACE) has been known for 100 years, the asymmetric cycloaddition of its 1-substituted derivatives is unknown. Herein, we report a supramolecular photochirogenic approach in which a homochiral and photoactive Δ/Λ-[Pd (RuL ) ] metal-organic cage (Δ/Λ-MOC-16) is used as a supramolecular reactor for the enantioselective exited-state photocatalysis of 1-Br-ACE. Owing to preorganization of the substrates by the supramolecular cage, stereochemical control of the triplet state, and nanospace transfer of energy and chirality, the cycloaddition of ACE proceeded with high selectivity for the formation of anti over syn stereoisomers, whereas the regio-, stereo-, and enantioselective cycloaddition of unsymmetrical 1-Br-ACE showed effective enantiodifferentiation of a pair of anti head-to-head stereoisomers. The enzyme-mimicking photocatalysis was verified by catalytic turnover, rate enhancement, and competing-guest inhibition experiments.
尽管苊（ACE）的光二聚化作用已经为人所知 100 年了，但它的 1-取代衍生物的不对称环加成反应却鲜为人知。在此，我们报告了一种超分子光致手性方法，其中使用手性和光活性的 Δ/Λ-[Pd（RuL）]金属有机笼（Δ/Λ-MOC-16）作为超分子反应器，用于 1-Br-ACE 的对映选择性激发态光催化。由于底物被超分子笼预组织，三重态的立体化学控制以及能量和手性的纳米空间转移，ACE 的环加成反应以高选择性形成反式异构体，而非对称的 1-Br-ACE 的区域、立体和对映选择性环加成反应则表现出一对反式头对头立体异构体的有效对映体分离。通过催化周转率、速率增强和竞争客体抑制实验验证了酶模拟光催化。
