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Development of New Radical Coupling Reactions at Carbon-Heteroatom Multiple Bonds

碳-杂原子多重键上新型自由基偶联反应的发展

基本信息

批准号：
14340229
负责人：
YAMAGO Shigeru
金额：
$ 9.02万
依托单位：
Osaka City University (2003-2004)Kyoto University (2002)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Radical mediated carbon-carbon bond formation at carbon-carbon multiple bonds, such as alkene and alkyne, has been widely utilized in organic synthesis due to its versatilities. However, little is known for the carbon-carbon bond formation at carbon-heteroatom multiple bonds, such as carbonyls and imines. This research was aimed to develop a new synthetic radical reaction at carbon-heteroatom multiple bonds based on the reaction of silyltellurides and carbon-heteroatom multiple bonds, which we have recently developed.A new coupling reaction of carbonyl compounds with alkynes mediated by trimethylsilylphenyltelluride has been developed. The reaction proceeded under mild thermal conditions to give the corresponding E-allylic alcohols bearing vinyltelluride group with high stereoselectivity. Furthermore, radical- and anion-mediated transformations of the vinyltellurides were highly useful for the stereoselective synthesis of multi-substituted alkenes. Therefore, the coupling reaction followed by the transformations provides a powerful strategy for the synthesis of multi-substituted alkenes with defined geometry.We have also developed a new coupling reaction of imines with isonitriles mediated by triethoxysilylphenyltelluride, a new class of silyltelluride reagent, to give α-silylaminomethylimidoyltellurides. The transformation of the carbon- tellurium bond in the coupling products afforded α-amino acid derivatives in good to excellent yields.The above mentioned radical coupling reactions as well as the subsequent synthetic transformations are insensitive to the substitutions of carbonyls, imines, alkynes, and isonitriles. Therefore, we clarified that the current method is suitable for the combinatorial synthesis of small molecule libraries.

自由基介导的碳-碳多重键形成反应，如烯烃和炔烃，由于其独特的性质，在有机合成中得到了广泛的应用。然而，很少有人知道在碳-杂原子多重键，如羰基和亚胺的碳-碳键的形成。基于近年来发展的碲化硅与碳-杂原子多重键的反应，提出了一种新的碳-杂原子多重键自由基合成反应，即三甲基碲化硅催化的羰基化合物与炔的偶联反应。反应在温和的热条件下进行，以高的立体选择性得到相应的带有乙烯基碲化物基团的E-烯丙醇。此外，自由基和阴离子介导的乙烯基碲化物的转化是非常有用的立体选择性合成的多取代烯烃。因此，偶联反应后的转化为合成具有特定几何构型的多取代烯烃提供了一个强有力的策略。我们还发展了一类新的碲化硅试剂--三乙氧基苯基碲化硅介导的亚胺与异腈的偶联反应，得到了α-甲硅氨甲基亚氨酰碲化物。偶联产物中的碳碲键的转化以良好的产率得到α-氨基酸衍生物.上述自由基偶联反应以及随后的合成转化对羰基、亚胺、炔和异腈的取代不敏感.因此，我们阐明了目前的方法适用于小分子文库的组合合成。