钯<em>ñ</em> - 杂环碳烯配合物：苯并咪唑盐的合成和碳 - 碳键合反应中的催化活性
Summary
给出了用于合成和随后从苯并咪唑鎓盐中纯化四种钯N-杂环卡宾络合物的详细和一般化方案。在芳基化和Suzuki-Miyaura反应中测试复合物的催化活性。对于所研究的每个反应，四种配合物中的至少一种成功地催化了反应。
Abstract
给出了用于合成和随后从苯并咪唑鎓盐中纯化四种钯N-杂环卡宾络合物的详细和一般化方案。还提供了详细的和一般的方案用于测试这种络合物在芳基化和铃木 – Miyaura交叉偶联反应中的催化活性。显示了四种配合物在芳基化和铃木 – 宫崎型反应中的催化活性的代表性结果。对于所研究的每个反应，四种配合物中的至少一种成功地催化了反应，使它们成为催化许多碳 – 碳键形成反应的有希望的候选物。所提出的方案一般足以适应于新的钯N-杂环卡宾络合物的合成，纯化和催化活性测试。
Introduction
N-杂环碳烯（NHC）引起了极大的关注，尤其是其催化各种重要反应的能力，如复分解，呋喃的生成，聚合，氢化硅烷化，氢化，芳基化，铃木 – 宫崎交联和Mizoroki-Heck交联1，2，3，4，5，6，7，8，9，10，11。 NHC可与金属结合;这种金属- NHC络合物作为辅助配体的过渡金属催化的反应被广泛使用和有机催化剂12，13，14， </SUP> 15，16。通常，由于金属 – 碳配位键17的高解离能，其对空气，水分和热量非常稳定。
这里，四个苯并咪唑盐（化合物1 – 4）先前示出的合成和纯化的协议及其钯NHC络合物（化合物5 -分别为8，）是详细18。先前使用各种技术来表征盐和络合物18 。由于用于芳基化和Suzuki-Miyaura交叉偶联反应9，10，11的催化相似的化合物，用于测试复合物的催化活性在芳基化和铃木-宫浦反应的类型，它们在还详细。重要的是，用于合成，纯化和测试复合物的催化活性的方案一般足够容易地适应新的钯NHC络合物。
Protocol
注意：使用许多挥发性溶剂作为下面详述的方案的一部分，以便在工作通风橱中进行所有实验。在使用前请穿戴适当的个人防护装备，并咨询各试剂的MSDS;在此提供有关危险试剂和步骤的简要信息。 苯并咪唑盐的合成和纯化（化合物1-4） 立即将100mL Schlenk管夹紧，并将搅拌棒，1mmol苯并咪唑，1mmol氢氧化钾和60mL乙醇作为溶剂。 注意：氢氧…
Representative Results
苯并咪唑的盐（1 – 4）（ 图1）在无水DMF使用N- -alkylbenzimidazoles和各种烷基卤化物，然后纯化和表征合成为前18，24日报道。它们是白色或奶油色固体，产率在62％至97％之间。钯络合物NHC（5 – 8）（ 图2）然后，从盐，纯化的合成…
Discussion
合成和纯化四种苯并咪唑鎓盐，随后他们的钯NHC络合物的方案被故意地提供给最大的细节，以帮助年轻的科学家或那些新的现场掌握他们。考虑到同样的目标，还详细介绍了在芳基化和铃木 – 宫古反应中测试四种络合物的催化活性的方案。此外，我们试图将方案呈现为尽可能一般的形式，以允许其他人容易地适应它们用于许多其它/新的钯NHC复合物的催化活性的合成，纯化和测试。
<p class="jove_c…Divulgaciones
The authors have nothing to disclose.
Acknowledgements
我们承认药学院（悉尼大学），Erciyes大学研究基金和TUBITAK（1059B141400496）的财务支持。我们感谢Tim Harland（悉尼大学）编辑视频。
Materials
| 1-chloro-4-nitrobenzene | Sigma-Aldrich (Interlab A.S., USA) | ||
| 2,5-dimethoxyphenylboronic acid | Sigma-Aldrich (Interlab A.S., USA) | ||
| 2-n-butylfuran | Sigma-Aldrich (Interlab A.S., USA) | ||
| 2-n-butylthiophene | Sigma-Aldrich (Interlab A.S., USA) | ||
| 3-chloropyridine | Merck (Darmstadt, Germany) | ||
| 4-bromoacetophenone | Merck (Darmstadt, Germany) | ||
| 4-bromoanisole | Sigma-Aldrich (Interlab A.S., USA) | ||
| 4-chlorotoluene | Sigma-Aldrich (Interlab A.S., USA) | ||
| 4-methoxy-1-chlorobenzene | Merck (Darmstadt, Germany) | ||
| 4-tert-butylphenylboronic acid | Sigma-Aldrich (Interlab A.S., USA) | ||
| Benzimidazole | Merck (Darmstadt, Germany) | ||
| Bromobenzene | Merck (Darmstadt, Germany) | ||
| Celite | Merck (Darmstadt, Germany) | ||
| Dichloromethane | Merck (Darmstadt, Germany) | ||
| Diethyl ether | Sigma-Aldrich (Interlab A.S., USA) | ||
| Ethyl acetate | Sigma-Aldrich (Interlab A.S., USA) | ||
| Ethyl alcohol | Merck (Darmstadt, Germany) | ||
| Hexane | Merck (Darmstadt, Germany) | ||
| Magnesium sulfate | Scharlau (Barcelona, Spain) | ||
| N,N-dimethylacetamide | Merck (Darmstadt, Germany) | ||
| N,N-dimethylformamide | Merck (Darmstadt, Germany) | ||
| Palladium chloride | Merck (Darmstadt, Germany) | ||
| Phenylboronic acid | Sigma-Aldrich (Interlab A.S., USA) | ||
| Potassium acetate | Merck (Darmstadt, Germany) | ||
| Potassium carbonate | Scharlau (Barcelona, Spain) | ||
| Potassium hydroxide | Merck (Darmstadt, Germany) | ||
| Silica gel | Merck (Darmstadt, Germany) | ||
| Sodium tert-butoxide | Merck (Darmstadt, Germany) | ||
| Thianaphthene-2-boronic acid | Sigma-Aldrich (Interlab A.S., USA) |
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Citar este artículo
Sahin, Z., Akkoς, S., İlhan, İ. Ö., Kayser, V. Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions. J. Vis. Exp. (125), e54932, doi:10.3791/54932 (2017).