Concise Synthesis of Well-Defined Linear and Branched Oligothiophenes with Nickel-Catalyzed Regiocontrolled Cross Coupling of 3-Substituted Thiophenes by Catalytically-Generated Magnesium Amide
Concise Synthesis of Well-Defined Linear and Branched Oligothiophenes with Nickel-Catalyzed Regiocontrolled Cross Coupling of 3-Substituted Thiophenes by Catalytically-Generated Magnesium Amide
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通过催化生成的氨基镁，通过镍催化 3-取代噻吩的区域控制交叉偶联，简明合成明确的线性和支化低聚噻吩
DOI：
10.1002/chem.201203331
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and Atsunori Mori
中科院分区：
文献类型：
--
作者：
Shota Tanaka;Daiki Tanaka;Go Tatsuta;Kohei Murakami;Shunsuke Tamba;Atsushi Sugie;and Atsunori Mori
通过3-取代噻吩的区域选择性去质子化和由此形成的金属化物质与溴噻吩的镍催化交叉偶联来进行具有明确结构的线性和支化低聚噻吩的合成。3-己基噻吩与EtMgCl和2，2，6，6-四甲基哌啶（TMP-H，10摩尔%）的反应通过使用催化产生的受阻氨基镁（TMPMgCl）在5-位选择性地诱导金属化，随后在镍催化剂存在下2-卤代-3-己基噻吩（溴化物或氯化物）的反应提供头-尾（HT）-型二聚体。 通过重复相同的顺序，以良好的产率合成线性低聚噻吩直至4聚体。3-己基噻吩与2，3-二溴噻吩的反应也发生，以定量产率提供支化低聚噻吩3-聚体。所获得的3-mer也以区域选择性方式在空间位阻较小的位置处金属化，在与2，3-二溴噻吩进一步偶联反应后以> 99%的产率提供7-mer。这些树枝状聚合物与几种多官能化的有机亲电试剂反应，产生各种支链低聚噻吩。
The synthesis of linear and branched oligothiophenes of well‐defined structures is performed with regioselective deprotonation of 3‐substituted thiophenes and nickel‐catalyzed cross‐coupling of the thus formed metalated species with a bromothiophene. The reaction of 3‐hexylthiophene with EtMgCl and 2,2,6,6‐tetramethylpiperidine (TMP‐H, 10 mol %) induces the metalation selectively at the 5‐position by use of the catalytically generated hindered magnesium amide (TMPMgCl) and the subsequent reaction of a 2‐halo‐3‐hexylthiophene (bromide or chloride) in the presence of a nickel catalyst affords a head‐to‐tail (HT)‐type dimer. By repeating the same sequence, the linear oligothiophene up to a 4‐mer is synthesized in good yield. The reaction of 3‐hexylthiophene with 2,3‐dibromothiophene also takes place to afford a branched oligothiophene 3‐mer in quantitative yield. The obtained 3‐mer is also metalated at the sterically less‐hindered position in a regioselective manner furnishing a 7‐mer in >99 % yield after a further coupling reaction with 2,3‐dibromothiophene. These dendrimers react with several multifunctionalized organic electrophiles, leading to a variety of branched oligothiophenes.