Novel formation of iodobenzene derivatives from 1-(methylthio)-3-tosylhexa-1,3-dien-5-ynes via iodine-induced intramolecular cyclization.
Novel formation of iodobenzene derivatives from 1-(methylthio)-3-tosylhexa-1,3-dien-5-ynes via iodine-induced intramolecular cyclization.
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DOI：
10.1021/jo701976q
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发表时间：
2008-02
期刊：
影响因子：
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通讯作者：
S. Matsumoto;K. Takase;K. Ogura
中科院分区：
文献类型：
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作者：
S. Matsumoto;K. Takase;K. Ogura
报道了(1E,3E)-1-（甲基硫）-3-tosylhexa-1,3-dien-5-ynes(3)与碘反应生成碘取代苯(4)。3与碘的反应进行得非常缓慢，但紫外线照射加速了反应，得到了高至优异收率的4。辐照诱导C1-C2双键顺反异构化，生成(1Z,3E)-几何异构体（3’），该异构体容易与碘反应生成4。该反应适用于3-（甲氧基羰基）-1-（甲基硫）-6-苯基己-1,3-二烯-5-炔（11），合成为几何混合物。有趣的是，这种混合物可以用作起始材料。用碘照射混合物（几何异构体比= 50:28:5:17），生成3-碘-4-苯基苯甲酸甲酯（12），收率为80%。
The reaction of (1E,3E)-1-(methylthio)-3-tosylhexa-1,3-dien-5-ynes (3) with iodine to form iodine-substituted benzenes (4) is reported. The reaction of 3 with iodine proceeded very slowly, but UV irradiation accelerates the reaction to give 4 in high-to-excellent yields. Irradiation induces the cis-trans isomerization of the C1-C2 double bond, leading to the (1Z,3E)-geometric isomer (3'), which easily reacts with iodine to afford 4. This reaction is applicable to 3-(methoxycarbonyl)-1-(methylthio)-6-phenylhexa-1,3-dien-5-yne (11), which is synthesized as a geometric mixture. Interestingly, this mixture can be used as the starting material. Irradiation of the mixture (the geometric isomer ratio = 50:28:5:17) with iodine resulted in the formation of methyl 3-iodo-4-phenylbenzoate (12) in 80% yield.