金属钯催化的碳-碳偶联反应
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金属钯催化的碳-碳偶联反应
中文
在有机化学中，C-C键的形成是有机合成研究的重要内容，而纳米过渡金属催化的偶联反应则是形成C-C键的一种有效手段。在经典的纳米过渡金属催化的C-C偶联反应的基础上，我们不断寻找新的催化剂，优化反应体系，以期使传统的C-C偶联反应达到更好的效果。本文中，我们采用一种新的磁性纳米Pd/Fe3O4/s-G催化剂，利用一锅法从芳胺衍生物出发，通过对反应条件的优化，分别采用亚硝酸叔丁酯和BF3•Et2O为重氮化试剂和添加剂，在甲醇溶剂中保持60 ℃反应5小时，经过重氮化/Suzuki偶联反应，成功实现了芳胺与芳基硼酸衍生物的交叉偶联反应。该反应是对经典Suzuki反应的有益补充，同时也为联芳基类化合物的形成提供了新的论文方法。与此同时，我们对新的磁性纳米Pd催化剂的循环实验进行了研究，结果表明，该催化剂能够重复使用4次并且保证催化效率基本不变，且易于通过磁性分离进行回收。 近几年来，非活性的C-H键官能化反应一直是有机化学中的研究热点。虽然在C-H活化方面各国的研究学者已经取得了很大进展，但是将C-H键直接转化成C-C、C-X、C-N、C-O、C-S键等，仍然是具有挑战性的课题。虽然已有多种官能团被用于导向的C-H键活化，但Pd催化的以乙酰基为导向基团的C-H活化反应目前仅有过一例报道。在本文中，我们以芳香酮类化合物和烯烃为底物，以Pd(OAc)2为催化剂，Cu(OAc)2•H2O为氧化剂，完成了酰基邻位sp2 C-H键活化氧化Heck反应。该反应是导向的氧化C-H官能化反应的一个新的发展。
译文
In the field of organic chemistry, the formation of C-C is an important content of
organic synthesis, while the nano transition-metal-catalyzed cross-couplings are the
effective measures of the formation of C-C. In the basement of classical C-C
cross-couplings, we keep looking for new catalysts and optimizing reaction systems in
order to make traditional C-C cross-couplings to achieve better effect. In this article, a
new, magnetic Pd/Fe3O4/s-G-catalyzed one-pot diazotization/cross-coupling of
anilines and arylboronic acids has been developed. Through the on-going optimation
of our reaction, we at last choose tBuONO as diazo reagent and
BF3•Et2O as the additive. The experiments are conducted in MeOH at sixty degrees
celsius and the reaction time is five hours. This process complemented the traditional
Suzuki cross-couplings and provided a more economic approach for the preparation
of biaryl products. At the same time, we have also studied the cycle test of our new
catalyst. It turned out that this kind of catalyst can be reused four times and the effect
is largely unchanged. The recycling of the catalyst is very convenient through
magnetic separation. In recent years, the activation of inact C-H has been the research focus of organic chemistry. Although there has been great progress on the activation
of C-H around the world, we still face huge challenges in transforming C-H to C-C,
C-X, C-N, C-O, C-S directly. There is only one case of Pd-catalyzed reactions about
the activation of C-H with acetyl as the directing group though a lot of functional
groups have been used in directed C-H activation. In this article, Pd(OAc)2 and
Cu(OAc)2•H2O are served as the catalyst and oxidant separately. We use aromatic
ketone derivatives and olefins as our reaction substrates and achieve the
ortho-activation of sp2 C-H and oxidative Heck reaction smoothly. This is a new
development of directed and oxidative functionalization of C-H.
