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lwn_2010

银虫 (正式写手)

[求助] MnCl2催化偶联KUMADA反应

我采用MnCl2催化合成沙坦联苯,催化剂的水分已除干净,溶剂THF水分含量已达指标,但却反应很不好,我想求助一下影响MnCl2催化的还有那些因素
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conlinkl

木虫 (正式写手)

【答案】应助回帖

The Kumada cross-coupling, also known as the Kumada-Corriu reaction, is a nickel catalyzed reaction between a Grignard reagent and an aryl halide. This organometallic reaction is very useful for C-C bond formation. It also works for alkyl and vinyl halides and in some cases, palladium catalysts can be used instead of nickel.

Read more: How to Do a Kumada Coupling | eHow.com http://www.ehow.com/how_6014768_ ... .html#ixzz1mY4CWp5w
1
Place your aryl halide (1 equivalent) in a dry reaction flask under an inert atmosphere such as nitrogen or argon. Add anhydrous diethyl ether and degas the solution by freeze-pump-thaw cycles or by bubbling with argon or nitrogen.

2
Next, you need to add your catalyst (typically 1-10 mol%) to the degassed reaction mixture as a solid. The catalyst is most often Ni(dppe)Cl2 (CAS: 14647-23-5), Ni(dppp)Cl2 (CAS: 15629-92-2) or Ni(dppf)Cl2 (CAS: 67292-34-6) but various other nickel and palladium catalysts have also been used widely.

3
From an addition funnel, you should now add a solution of your Grignard reagent (a slight excess, either freshly prepared or from a commercial source) to the reaction mixture and subsequently warm the reaction mixture to gentle reflux. The reaction will typically go to completion with reflux over night.

4
Workup typically consists of an aqueous wash followed by column chromatography and recrystallization to afford your desired product.



Read more: How to Do a Kumada Coupling | eHow.com http://www.ehow.com/how_6014768_ ... .html#ixzz1mY46yNzO
人生为棋我愿为卒,虽步履缓慢可谁曾见我后退一步
2楼2012-11-07 20:56:44
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心身一体

金虫 (著名写手)

菜芽

师兄你好,我是研一的有机化学的学生! 不知道您做的 MnCl2催化的Kumada反应后面做的怎么样啦? 学弟我现在做这个也遇到问题了,,,收率较低,,,而且老师还要求不要让格式试剂过量,还请师兄指点密经!不知道有没有相关文献? 我一直没有搜索到!

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君欲善其事必先利其器善,始善终。珍惜,态度,责任。。
3楼2016-03-06 17:19:16
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