A simple and powerful tool for preparing uncommon bromoarenes via the unsymmetrization of a naphthalene ring was developed. The steric repulsion between the peri-bromo groups of 1,8-dibromonaphthalene distorts the naphthalene ring, allowing for nonelectronical activation. Ring distortion facilitates the 1,2-rearrangement of the bromo group, affording 1,7-dibromonaphthalene upon treatment with trifluoromethanesulfonic acid (halogen dance reaction). For 1,4,5,8-tetrabromonaphthalene, stepwise 1,2-rearrangements proceeded successively to furnish 1,3,5,7-tetrabromonaphthalene. Density functional theory calculations suggest that this reaction is initiated by ipso-protonation, with a subsequent 1,2-rearrangement occurring via the bromonium transition state. Utilizing 1,7-dibromonaphthalene, which is characterized by two C–Br bonds arranged at a 60° angle, a unique metal–organic framework comprising a 52-membered ring network was synthesized.

中文翻译：

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酸诱导卤素舞蹈反应导致 1,8-二溴萘不对称化


开发了一种简单而强大的工具，用于通过萘环的不对称化来制备罕见的溴代芳烃。 1,8-二溴萘的邻溴基团之间的空间排斥使萘环变形，从而实现非电子激活。环畸变促进溴基团的 1,2-重排，用三氟甲磺酸处理后得到 1,7-二溴萘（卤素舞反应）。对于1,4,5,8-四溴萘，连续进行逐步1,2-重排以提供1,3,5,7-四溴萘。密度泛函理论计算表明，该反应是由原质子化引发的，随后通过溴过渡态发生 1,2-重排。利用1,7-二溴萘的特征是两个以60°角排列的C-Br键，合成了包含52元环网络的独特金属有机骨架。