Studies on New Cross-Coupling Reactions : The Cleavage and Formation of C-C Bonds

近年来，有效的碳碳键形成反应因其在合成各种有机功能材料和生物活性物质方面的应用而备受关注。我们已经成功地开发了一些新的芳香族和不饱和化合物的催化偶联反应，这些反应涉及碳-碳和/或碳-氢键的断裂和碳-碳键的形成。本研究的目的是提高它们的效率和选择性，并开发其他相关的新反应。用各种后过渡金属催化剂初步考察了含羧基和羟基的芳香族底物与炔烃或烯烃的催化反应。在Rh催化下，芳香族羧酸与内炔反应中，通过碳氢键断裂有效地进行了1：1的氧化偶联反应，选择性地生成了异香豆素衍生物。另一方面，在同一底物的反应中，在Ir催化下，以1：2的氧化偶联方式唯一地生成了萘衍生物。后一种反应似乎涉及羧基引导的区域选择性碳氢键断裂和随后的脱羧基作用。研究还发现，这种独特的可移除官能团可以在其周围引发新的偶联反应。因此，含吲哚和噻吩环的杂芳羧酸在钯催化下顺利地进行了区域选择性的乙烯化、甲基化和脱羧化反应。我们还研究了一些其他相关的联轴器，并成功地开发出了它们。通过这项研究获得的结果已被学术论文和国内外会议上的演讲广泛报道。

Recently, effective carbon-carbonbond forming reactions have attracted much attention due to their utility for the synthesis of a variety of organic functional materials and biologically active agents. We have successfully developed a number of new catalytic coupling reactions of aromatic and unsaturated compounds which involve carbon-carbon and/or carbon-hydrogen bond cleavage and carbon-carbon bond formation. The purpose of this study is to improve their efficiency and selectivity and to develop other related new reactions. The catalytic reactions of aromatic substrates possessing carboxyl and bydroxyl groups with alkynes or alkenes were initially examined using various late transitionmetal catalysts. During the treatment of aromatic carboxylic acids with internal alkynes under rhodium catalysis, the oxidative 1:1 coupling efficiently proceeded via carbon-hydrogen bond cleavage to selectively give isocoumarin derivatives. On the other hand, in the reaction of same substrates under iridium catalysis, naphthalene derivatives were exclusively formed by the oxidative 1:2 coupling. The latter reaction appears to involve regioselective carbon-hydrogen bond cleavage directed by the carboxyl group and subsequent decarbaxylation. It was also found that the unique removable functional group can induce new coupling reactions around it. Thus, heteroaromatic carboxylic adds possessing indole and thiophene rings smoothly underwent the regioselective vinylation and mylation accompanied by decarboxylation under palladium catalysis. We also examined a number of other related couplings and succeeded to develop them. The results obtained through this study have been reported widely by academic papers and presentations in domestic and international conferences.