One-step synthesis of triethynylvinylmethanes and tetraethynylmethanes by GaCl3-promoted diethynylation of 1,4-enynes and 1,4-diynes
One-step synthesis of triethynylvinylmethanes and tetraethynylmethanes by GaCl3-promoted diethynylation of 1,4-enynes and 1,4-diynes
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DOI：
10.1021/ja051416l
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发表时间：
2005-06-15
影响因子：
15
通讯作者：
Yamaguchi, M
中科院分区：
文献类型：
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作者：
Amemiya, R;Suwa, K;Yamaguchi, M
1，4-烯炔与氯三乙基硅基乙炔在130 °C和GaCl_3存在下反应，烯丙基亚甲基部分发生二乙炔化反应，生成三乙炔基乙烯基甲烷。2，6-二（叔丁基）-4-甲基吡啶和叔丁基二苯基硅醇的加入，通过减少底物和产物的分解，大大提高了产物的产率。该反应应该涉及烯炔和GaCl 3的初始形成烯丙基镓，其中GaCl 3活化烃C-H以生成亲核有机镓中间体。用氯乙炔进行碳化，然后进行β-消除，得到乙炔化产物。在烯炔的3-位上进行重复的区域选择性乙炔化反应，得到三乙炔基乙烯基甲烷。烯丙基硅烷与氯乙炔的反应也产生二乙炔基乙烯基甲烷，其中1，4-烯炔是通过烯丙基硅烷和GaCl 3形成的烯丙基镓的加成-消除反应原位形成的。通过使1，4-二炔与氯乙炔在150 °C下反应获得四乙炔基甲烷。硅烷醇的结构和量可以用来控制GaCl 3的反应性。
The treatment of 1,4-enynes with chlorotriethylsilylacetylene at 130 °C in the presence of GaCl3gave triethynylvinylmethanes by the diethynylation at the allylic methylene moiety. The addition of 2,6-di(tert-butyl)-4-methylpyridine andtert-butyldiphenylsilanol considerably improved the yields of the products by reducing the decompositions of the substrates and products. The reaction should involve the initial formation of allylgallium from the enynes and GaCl3, where GaCl3activated hydrocarbon C−H to generate a nucleophilic organogallium intermediate. Carbometalation with chloroacetylene followed by β-elimination then led to the ethynylated product. Triethynylvinylmethanes were obtained by the repeated regioselective ethynylation at the 3-position of the enynes. The reaction of allylsilanes with the chloroacetylene also gave diethynylvinylmethanes, in which 1,4-enynes were formed in situ by the addition−elimination of allylgallium formed from allylsilane and GaCl3. Tetraethynylmethanes were obtained by reacting 1,4-diynes with the chloroacetylene at 150 °C. The structure and amount of silanol can be used to control the reactivity of GaCl3.