基于氮、氧配位的导向sp~2碳氢键氧化偶联反应研究

【作者】 张春；

【导师】 孙培培；

【作者基本信息】 南京师范大学 ， 有机化学， 2015， 硕士

【摘要】 过渡金属催化的碳氢键活化/官能化反应已经为碳碳键或碳杂键的构建提供了一种非常经济和绿色的合成方法,因此,一些需要零价钯催化的惰性芳烃的官能团化反应,比如Heck反应等,现在已经不再需要一系列繁琐的步骤了。本文主要介绍了两个通过碳氢键活化进行的新颖的合成方法：钯催化的酚羟基导向的sp2碳氢键活化的烯基化反应和钯催化的2-苯氧基吡啶的sp2碳氢键活化烷氧基化反应。在有机合成中,羟基是一个非常重要的官能团,同时,它也具有较弱的与过渡金属的配位能力。这种特性使它在过渡金属催化的导向官能团化反应中扮演着十分重要的角色。我们建立了一个基于钯的催化体系,并成功的在此体系中实现了2-芳基苯酚的碳氢键活化烯基化反应,高选择性地合成了2-(2’-烯基苯基)苯酚,产率在中等左右。该反应可以在空气氛围下进行,反应条件较为温和,而且产物的产率中等,具有较高的立体选择性。与过渡金属催化的芳环的导向碳碳键构建相比,惰性烃类的烷氧基化反应更加的困难,并且需要更深入的研究。另一方面,2-苯氧基吡啶类化合物有着较高的生物活性,并且在医药领域受到了广泛的关注。在此基础上,我们建立了一个高效的具有高选择性的钯催化的2-苯氧基吡啶邻位的烷氧基化反应,在此反应中,我们使用2-吡啶氧基作为导向基团,脂肪醇作为烷氧基化试剂,该反应中,伯醇和仲醇都具有较好的反应活性,且能在空气氛围中很顺利的进行反应,反应条件温和,这些都使该反应十分实用。更多还原

【Abstract】 Transition-metal-catalyzed C-H bond activation/functionalization has constituted an expedient carbon-carbon and carbon-heteroatom bond formation protocol with features of step economy and green chemistry primarily, and therefore, laborious arene prefunctionalization like that required for traditional palladium(0)-catalyzed cross-coupling reactions such as the Mizoroki-Heck reaction would be or is now no longer required in many cases. This thesis introduced two novel synthetic methods via directing C-H functionalizations:palladium-catalyzed alkenylation via sp2 C-H bond activation using phenolic hydroxyl as the directing group and palladium-catalyzed direct C(sp2)-H alkoxylation of 2-aryloxypyridines using 2-pyridyloxyl as the directing group.Hydroxyl is a very important functional group in organic chemistry, and also, it exhibits weak coordination to transition metals. This characteristic enables it to play an important role in several transition-metal-catalyzed transformations. We have developed a new Pd-based catalytic system that successfully effects C-H alkenylation of 2-arylphenols to produce 2-(2’-alkenylphenyl)phenols selectively in moderate to good yields. The reaction proceeds in an atmosphere of air under relatively mild reaction conditions which can tolerate a series of functional groups and provides the alkenylation products regio-and stereoselectively in moderate to good yields.Compared with the transition-metal-catalyzed direct aromatic C-C bond formation reaction, the alkoxylation of inert C-H is more difficult and still needed to be studied more adequately. On the other hand,2-phenoxypyridine series compounds have interesting bioactivities and have aroused much attention in the pharmaceutical field. Therefore, an efficient and highly regioselective palladium catalyzed ortho-C(sp2)-H bond alkoxylation of 2-aryloxypyridines was developed using 2-pyridyloxyl as the directing group and alcohols as alkoxylation reagents. This technology was available for both primary and secondary alcohols. The reaction could proceed smoothly in an air atmosphere under mild reaction conditions, making the method highly applicable.更多还原