An Unexpected Double Diels–Alder Reaction of (E)‐2‐Bromo‐4‐aryl‐1,3‐pentadiene Involving [1,5]‐Hydrogen Migration and HBr Elimination: Synthesis of Bicyclo[2.2.2]octene Derivatives |
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| Authors: | Pingping Huang Dr. Lingyan Liu Weixing Chang Prof. Jing Li |
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| Affiliation: | State Key Laboratory of Elemento‐Organic Chemistry, The Department of Chemistry, Nankai University, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Weijin Road 94#, Nankai District, Tianjin 300071 (P.R. China) |
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| Abstract: | An unexpected double Diels–Alder (DDA) reaction of (E)‐2‐bromo‐4‐aryl‐1,3‐pentadiene was developed and resulted in a series of “butterfly‐like” bicyclo[2.2.2]octene derivatives in moderate to good yields without the need for a metal catalyst. The proposed mechanism involves a [1,5]‐sigmatropic hydrogen migration and HBr elimination. Through this decisive [1,5]‐hydrogen shift step, the electronic properties and steric hindrance of the conjugated diene substrate are completely altered and the DDA reaction of this potential diene synthon is successfully achieved. |
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| Keywords: | conjugated dienes cycloaddition maleimides hydrogen migration synthesis design |
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