Abstract

Ever since the halogen dance reaction was discovered by Bunnet et al, synthetic chemists have utilized the transformation in many desirable ways to build substituted heterocyclic target molecules of all kind. Using DFT-Cam-B3LYP/ land2dz computations and focused on Hannes Frohlich et al. Halogen Dance (HD) reactions of bromothiophenes, a new bromo-bridged Transition State (TS) is proposed. This bromo-bridged TS was then used to put forth eight possible isomerization as well as eight possible disproportionation paths. These mechanistic pathways were then carefully inspected based on TS’s energy and protonation/deprotonation steps to find the most suitable pathways. Collectively these mechanistic pathways joined like a jigsaw puzzle to give, for the first-time, a fully comprehensive cascade-like pattern for base-catalyzed halogen dance in its entirety. The present work may well shed light on a dynamic domino mechanism which dominates the realm of nonaqueous strongly basic medium, organic chemistry, reactions.

Graphic abstract

C-Br reactivity and σ-holes in bromothiophenes are shown to be the major mechanistic driving force in their base catalyzed Halogen dance reactions.

中文翻译：

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溴噻吩中卤素舞反应的机制途径：级联状模式

摘要

自从Bunnet等人发现卤素舞反应以来，合成化学家就已经以许多理想的方式利用了这种转化，以构建各种取代的杂环目标分子。使用DFT-Cam-B3LYP / land2dz计算并集中于Hannes Frohlich等。提出了一种新的溴桥过渡态（TS），用于溴噻吩的卤素舞（HD）反应。然后使用该溴桥连的TS提出八种可能的异构化以及八种可能的歧化路径。然后根据TS的能量和质子化/去质子化步骤仔细检查这些机械途径，以找到最合适的途径。这些机械途径总体上像拼图游戏一样，首次为碱基催化的卤素舞提供了一种全面的，类似瀑布的图案。目前的工作可以很好地揭示动态多米诺机制，该机制主导着非水强碱性介质，有机化学，反应领域。

图形摘要

溴噻吩中的C-Br反应性和σ孔是它们在碱催化的卤素舞反应中的主要机理驱动力。