再生三乙基胺及有機膦試劑:經良好的化學選擇性及分子內 Wittig 反應合成四取代呋喃化合物及利用苯炔與亞胺經由 π 鍵的嵌入反應合成苯并噁嗪化合物

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2016

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我們使用催化量的三乙基胺以及有機膦試劑進行分子內 Wittig 反應合成四取代呋喃化合物,在反應中我們使用三乙基氯矽烷作為啟動試劑,用來活化氧化膦,再利用苯基矽烷對氧化膦進行還原反應。在反應中我們發現三乙基氯矽烷做為反應中的啟動試劑,進而促進還原反應,且催化量的三乙基胺鹽可以藉由加熱再生成三乙基胺。因此我們在反應中建立雙循環系統,且在系統中的各個試劑皆有良好的化學選擇性。並可以使用多種取代基的起始物,如氰基、酯基及酮基等來進行反應,並得到不錯的產率。 關鍵字 : 三乙基胺、有機膦試劑、Wittig 反應、四取代呋喃化合物。 苯炔為高活性的反應中間體,因其多樣化的反應吸引許多化學家的注意,因此我們嘗試利用苯炔與高活性且缺電子性質的氮-烯基亞胺反應。出乎我們意料之外得到的產物為經由 π 鍵的嵌入反應形成苯并噁嗪化合物,我們也可以使用取代基的芳香炔化合物與氮-醯基亞胺進行反應,來探討其化學選擇性。 關鍵字 : 苯炔、亞胺。
An efficient protocol for the synthesis of highly functionalized furans via intramolecular Wittig reaction has been developed using catalytic amounts of phosphine and triethylamine in the presence of silyl chloride, which served as the promoter to activate the phosphine oxide. Reduction of the activated phosphine oxide by hydrosilane resulted in the generation of phosphine, while the decomposition of conjugate acid of Et3N resulted in the regeneration of base, both of which mediated the formation of phosphorus ylide. Key word : trimethylamine, phosphine, Wittig reaction, functionalized furans. Because arynes are highly reactive species and can undergo a variety of transformations, their chemistry attract chemist a lot of attention. We have successfully utilized the eletron-deficient N-acyl imines to trap the in-situ generated intermediates, benzyne, to obtain the corresponding benzoxazine derivatives in moderate yield. These unprecedented reactions are assumed to be via an unexpected [2+2] cycloaddition of N-acyl imine and benzyne as the key step. Key word : Arynes, N-Acyl imines.

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三乙基胺, 有機膦試劑, Wittig 反應, 四取代呋喃化合物, 苯炔, 亞胺, triethylamine, phosphine, Wittig reaction, functionalized furans, Arynes, N-Acyl imines

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