Photoinduced Tandem Three-Component Coupling of Propanedinitrile, 2,5-Dimethylhexa-2,4-diene, and Cyanoarenes
Photoinduced Tandem Three-Component Coupling of Propanedinitrile, 2,5-Dimethylhexa-2,4-diene, and Cyanoarenes
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DOI：
10.1021/jo801624q
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发表时间：
2008-11-07
影响因子：
3.6
通讯作者：
Mizuno, Kazuhiko
中科院分区：
文献类型：
--
作者：
Ohashi, Maki;Nakatani, Keisuke;Mizuno, Kazuhiko
在含有丙二腈（1，丙二腈），2，5-二甲基己-2，4-二烯（2）的MeCN/H_2O溶液中，光照射下发生串联的三组分偶联光反应。和聚氰基芳烃在菲和碳酸酯的存在下，导致1的选择性α-单烷基化。该反应通过光NOCAS（亲核-烯烃组合，芳香取代）型机制进行：1的阴离子亲核攻击光生2（中心点+），然后在聚氰基芳烃的自由基阴离子上进行ipso取代。它在温和、安全和环境友好的条件下进行，如在环境温度下进行，不含金属和卤素，以及在弱碱的存在下进行。该反应也代表了一种新的和无金属的交叉偶联反应，导致ipso取代聚氰基芳烃通过芳基-氰基键断裂。此外，该反应是除氰离子外，在光诱导电子转移反应中引入碳亲核试剂的一个罕见的例子。
A tandem three-component coupling photoreaction proceeds upon photoirradiation of MeCN/H2O solutions containing propanedinitrile (1, malononitrile), 2,5-dimethylhexa-2,4-diene (2). and polycyanoarenes in the presence of phenanthrene and carbonate, leading to selective alpha-monoalkylation of 1. The reaction proceeds via photo-NOCAS (Nucleophile-Olefin Combination, Aromatic Substitution) type mechanism: nucleophilic attack of the anion of 1 to photogenerated 2(center dot+) is followed by ipso-substitution on the radical anion of the polycyanoarene. It advances under mild, safe, and environmentally friendly conditions Such as proceeding at ambient temperature without metals and halogens, and in the presence of Weak base. The reaction also represents a novel and metal-free cross-coupling reaction that leads to ipso-substitution on polycyanoarene via aryl-cyano bond cleavage. In addition, the reaction is a rare example of introducing carbon nucleophile in the photoinduced electron transfer reaction, except that of cyanide ion.