Incorporating Ester Functionality within a Solid-State [2 + 2] Cycloaddition Reaction Based Upon Halogen Bonding Interactions
Incorporating Ester Functionality within a Solid-State [2 + 2] Cycloaddition Reaction Based Upon Halogen Bonding Interactions
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DOI：
10.1021/acs.cgd.9b01624
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发表时间：
2020-02
影响因子：
3.8
通讯作者：
Samantha J. Kruse;E. Bosch;F. Brown;R. Groeneman
中科院分区：
文献类型：
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作者：
Samantha J. Kruse;E. Bosch;F. Brown;R. Groeneman
基于 1,4-二碘全氯苯 (C6I2Cl4) 作为卤素键供体以及一系列异构吡啶乙烯基酯，即 (E)-甲基-3-(吡啶-X-基)丙-2-烯酸酯（其中 X = 4、3 和 2）(4-PAMe)、(3-PAMe) 和 (2-PAMe) 形成共晶， 已经实现了。在所有情况下，C6I2Cl4 卤素与吡啶氮原子和酯氧原子的组合键合，产生延伸的固体。观察到共晶(C6I2Cl4)•(4-PAMe)和(C6I2Cl4)•2(3-PAMe)具有光反应性。 X射线结构分析表明，C6I2Cl4分子以均匀的面对面π-π方向堆叠，然后将一对碳碳双键（C=C）以正确的方向定位，以进行固态[2+2]环加成反应。因此，在暴露于紫外线下时，(C6I2Cl4)•(4-PAMe) 和 (C6I2Cl4)•2(3-PAMe) 都会发生区域选择性和定量光反应，产生头对头光产物，即 (rctt)-二甲基-3,4-双(吡啶-4-基)环丁...
The formation of co-crystals based upon 1,4-diiodoperchlorobenzene (C6I2Cl4) as a halogen bond donor along with a series of isomeric pyridine vinyl esters, namely (E)-methyl-3-(pyridine-X-yl)prop-2-enoate (where X = 4, 3, and 2) (4-PAMe), (3-PAMe), and (2-PAMe), has been achieved. In all cases, C6I2Cl4 halogen bonds to a combination of pyridine nitrogen atoms as well as ester oxygen atoms to yield an extended solid. The co-crystals (C6I2Cl4)•(4-PAMe) and (C6I2Cl4)•2(3-PAMe) were observed to be photoreactive. X-ray structural analysis revealed that molecules of C6I2Cl4 are stacked in a homogeneous face-to-face π-π orientation which then positions a pair of carbon-carbon double bonds (C=C) in the correct orientation to undergo a solid-state [2 + 2] cycloaddition reaction. Thus, upon exposure to ultraviolet light, both (C6I2Cl4)•(4-PAMe) and (C6I2Cl4)•2(3-PAMe) undergo a regioselective and quantitative photoreaction to yield the head-to-head photoproduct, namely (rctt)-dimethyl-3,4-bis(pyridin-4-yl)cyclobuta...