目录
摘要I
关键词I
AbstractII
引言
1引言1
1.1催化量叔膦促进的Wittig反应 1
1.2催化量叔膦促进的azaWittig反应7
2课题的提出与设计8
3仪器与试剂 8
3.1本实验所用的主要仪器8
3.2本实验所用的主要试剂 9
4结果与分析 9
4.1反应条件优化 9
4.2底物拓展 10
4.3机理探究 11
4.4实验部分 13
4.4.1实验操作 14
4.4.2代表性化合物的相关表征数据 14
5论文小结 14
致谢15
参考文献15
催化量叔膦促进的多组分反应合成多取代呋喃及其机理研究
摘 要
Wittig反应常被用于有效构建碳碳双键，在有机合成中占有十分重要的地位。然而，Wittig反应自身的一些缺陷限制了其应用的广泛性，主要原因在于使用了化学计量的有机磷试剂。反应生成的化学计量的氧化磷副产物会给提纯目标产物带来困难，使其难以在工业上大规模运用。同时，大部分特殊结构以及手性的磷试剂价格十分昂贵，导致Wittig反应在不对称合成中的应用受到一定限制。近年来，化学家们发现硅烷作为还原剂可以高效还原氧化磷，并且对底物官能团具有很好的兼容性，因而硅烷还原策略成功用于将一系列化学计量有机磷促进的反应转化为催化量有机磷促进的反应。在本论文中，我们发展了一种以末端活化烯烃和酰氯或酸酐为底物，通过多组分反应合成多取代呋喃的方法。在该反应中，不再需要使用化学计量的nBu3P，催化量的nBu3P即可以中等到优秀的收率得到相应的产物，还原剂硅烷在反应体系中有较好的底物兼容性。机理研究表明，nBu3P在反应体系中能有效再生，同时，在硅烷存在下nBu3P=O可以作为nBu3P的等价物使用。该合成方法以硅烷驱动的分子内Wittig反应为关键步骤，代表了催化量叔膦促进的Wittig反应在多组分反应中的成功应用。
SYNTHESIS OF POLYSUBSTITUTED FURANS VIA CA *51今日免费论文网|www.51jrft.com +Q: ^351916072* 
TALYTIC PHOSPHINE MEDIATED MULTICOMPONENT REACTIONS AND ITS MECHANISTIC STUDY
ABSTRACT
The Wittig reaction provides a powerful tool for convenient construction of carboncarbon double bonds in synthetic chemistry. Despite the popularity of this reaction, some major drawbacks are associated with the formation of stoichiometric phosphine oxides as byproducts. The troublesome purification of the byproducts makes them valueless on an industrial scale. Also, most welldesigned phosphines, especially chiral phosphine reagents, are very expensive and high cost hampers their applications in asymmetric Wittig reaction. Recently, silanes have been recognized as powerful reducing agents for insitu deoxygenation of phosphine oxides with good functional tolerance after a series of successful applications of silanes in the transformation of a stoichiometric phosphinemediated reaction into a catalytic one. In this dissertation, polysubstituted furans have been prepared from terminal activated olefins and acylchlorides or anhydrides by a multicomponental convergent synthesis mode. Instead of stoichiometricn nBu3P, only catalytic nBu3P is needed to furnish the furans in modest to excellent yields with a good functional group tolerance under the aid of reducing agent silane. Mechanistic study indicates that nBu3P can be regenerated infectively in the reaction conditions and nBu3P=O was equivalent catalyst of nBu3P in the presence of silane. This synthetic method features a silanedriven catalytic intramolecular Wittig reaction as a key annulation step and represents a successful application of catalytic Wittig reaction in multicomponent cascade reaction.

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