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<p><i>meta</i>-Cyclophanes represent a ubiquitous and versatile structural motif in macrocycles. While conventional synthetic strategies predominantly rely on end-to-end cyclization, these methods are often hampered by unfavourable enthalpic and entropic constraints, and are limited to unstrained <i>meta</i>-cyclophanes. Here we present an aryne-mediated ring-expansion strategy based on sequential aryne insertion into the S=O bond of cyclic sulfoxides followed by an anionic [4,5]-sigmatropic rearrangement. A pivotal aspect of this strategy is the ability of the generated phenolate oxygen to redirect the rearrangement pathway from a [5,5]- to an anionic [4,5]-sigmatropic rearrangement. This methodology enables efficient access to strained <i>meta</i>-cyclophanes with diverse substitution patterns. Moreover, it not only supports the use of <i>meta</i>-cyclophane-based aryne precursors but also enables the orthogonal assembly of a secondary cyclophane ring on the antipodal face of the central benzene scaffold. Furthermore, a chirality transfer process is observed, underscoring the stereospecific nature of both the S=O bond insertion and the [4,5]-sigmatropic rearrangement steps.</p><p></p>

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Preparation of meta-cyclophanes via stereospecific ring-expansion rearrangement

  • 期刊论文

  • 发表日期：

    2026年3月2日

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  • Min Tan,
  • Yongsheng Shen,
  • Haohua Chen,
  • Wenfu Yan,
  • Dachuan Qiu,
  • Yang Li

摘要

meta-Cyclophanes represent a ubiquitous and versatile structural motif in macrocycles. While conventional synthetic strategies predominantly rely on end-to-end cyclization, these methods are often hampered by unfavourable enthalpic and entropic constraints, and are limited to unstrained meta-cyclophanes. Here we present an aryne-mediated ring-expansion strategy based on sequential aryne insertion into the S=O bond of cyclic sulfoxides followed by an anionic [4,5]-sigmatropic rearrangement. A pivotal aspect of this strategy is the ability of the generated phenolate oxygen to redirect the rearrangement pathway from a [5,5]- to an anionic [4,5]-sigmatropic rearrangement. This methodology enables efficient access to strained meta-cyclophanes with diverse substitution patterns. Moreover, it not only supports the use of meta-cyclophane-based aryne precursors but also enables the orthogonal assembly of a secondary cyclophane ring on the antipodal face of the central benzene scaffold. Furthermore, a chirality transfer process is observed, underscoring the stereospecific nature of both the S=O bond insertion and the [4,5]-sigmatropic rearrangement steps.