烯基自由基與矽基酮進行自由基連繼性環化反應的研究

本實驗室之前針對矽基酮與烯基自由基環化反應的研究，顯示出此類化合物具有開發連繼性環化反應的可能。烯基自由基環化後所得到β-矽基烷氧自由基，經過Brook重排，產生因共振而穩定的烯丙基自由基。此系統最特殊的地方在於雙鍵的存在，自由基中間體可以透過共振使得三號碳的位置上具有自由基性質。我們利用這種特性，希望將此形式的反應發展為連繼性環化反應。我們的構想是利用炔基做為自由基受體，利用三號碳所具有的自由基性質，進行第二次環化反應，架構出雙環化合物。本文設計出兩種類型的環化前驅物進行研究。

關鍵字

自由基；環化反應；矽基酮；丙烯基自由基

並列摘要

According to previous research in our laboratory, cyclizations of acylsilanes with vinyl radicals have been studied. This process involved intramolecular free radical cyclizations of a vinyl radical to the carbonyl group of acylsilane to give a β-silyl alkoxy radical. This radical then undergoes a radical Brook rearrangement to afford an α-silyloxy radical. Due to the presence of the vinyl group, this α-silyloxy radical is also an allylic radical. Finally, hydrogen abstraction occurs at the γ-position of this allylic system to give an enol silyl ether. Generally, 1,5-exo-cyclizations are more efficient than 1,6-exo-cyclizations. In this research we exploited this system further in the context of tandem radical cyclizations. We have constructed two systems in which the intermediate allylic radicals are trapped intramolecularly at the γ-position by radicalphilic groups. Specifically, we have synthesized acylsilanes with vinyl iodide tethered to an alkynyl functional group. The scope and limitations of this type of tandem cyclizations were studied.

並列關鍵字

radical ； cyclization ； acylsilane ； vinyl radical

參考文獻

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國際替代計量

烯基自由基與矽基酮進行自由基連繼性環化反應的研究

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