Strain-Driven Formal [1,3]-Aryl Shift within Molecular Bows |
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Authors: | Liang Jiang Zhen Peng Yimin Liang Zheng-Bin Tang Kejiang Liang Jiali Liu Prof Zhichang Liu |
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Institution: | 1. Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 China;2. Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Westlake Institute for Advanced Study, 600 Dunyu Road, Hangzhou, Zhejiang 310030 China |
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Abstract: | Delving into the influence of strain on organic reactions in small molecules at the molecular level can unveil valuable insight into developing innovative synthetic strategies and structuring molecules with superior properties. Herein, we present a molecular-strain engineering approach to facilitate the consecutive 1,2]-aryl shift (formal 1,3]-aryl shift) in molecular bows (MBs) that integrate 1,4-dimethoxy-2,5-cyclohexadiene moieties. By introducing ring strain into MBs through tethering the bow limb, we can harness the intrinsic mechanical forces to drive multistep aryl shifts from the para- to the meta- to the ortho-position. Through the use of precise intramolecular strain, the seemingly impractical 1,3]-aryl shift was realized, resulting in the formation of ortho-disubstituted products. The solvent and temperature play a crucial role in the occurrence of the 1,3]-aryl shift. The free energy calculations with inclusion of solvation support a feasible mechanism, which entails multistep carbocation rearrangements, for the formal 1,3]-aryl shift. By exploring the application of molecular strain in synthetic chemistry, this research offers a promising direction for developing new tools and strategies towards precision organic synthesis. |
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Keywords: | Aryl Shift Carbocation Rearrangement Mechanochemistry Molecular-Strain Engineering Strained Structure |
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