【作者】 韩志勇；

【导师】 龚流柱；

【作者基本信息】 中国科学技术大学 ， 有机化学， 2011， 博士

【摘要】 多催化剂不对称合成是新近发展起来的一类合成方法学。两种或两种以上在催化剂在共存于同一反应体系中,或相互协作公共促进反应的发生,或互不影响各自完成串联反应中的一步。应用这种策略不但能够实现传统单一催化剂无法完成的反应,而且能够减少溶剂的消耗、废物的排放,有效提高反应的原子经济性,在石油、天然气等化工原料日益减少的今天显得尤为重要。将金属催化剂与有机小分子催化剂组成协同或接力催化体系,可以发挥传统金属类催化剂的长处,弥补有机催化剂活化模式相对较少、所能作用的官能团有限等不足,该领域已逐渐受到各国化学家的关注。要成功地将多种催化剂结合到一个反应体系中,就必须要保证体系中各各种组分能够相互兼容,避免催化剂失活、底物分解等情况的发生。我们发现,金配合物能够与联萘酚衍生的手性磷酸很好地兼容。我们应用非手性金配合物和手性磷酸组成接力催化体系,从2-(2-丙炔基)苯胺一步高效合成了四氢喹啉。反应条件温和,反应进行迅速、彻底,有很高的产率和ee值。我们所提出的方法,不光为不对称合成四氢喹啉提供了较好的方法,还为金属/有机协同、接力催化循环设计提供了重要借鉴。同样使用非手性金配合物和手性磷酸组成接力催化体系,我们实现了炔醇环化串联与吖内酯的aldol-type反应,高收率、高对映选择性地合成了一类含有相邻两个季碳手性中心的化合物。该类化合物可以衍生为具有空间张力的氨基酸,可以应用于合成具有生理活性的强张力多肽类化合物。我们还研究了手性磷酸催化的1,5-苯并二氮杂卓类化合物的动态动力学还原反应,为手性1,3-二胺的合成提供了新的方法。更多还原

【Abstract】 Multi-catalysts system have emerged as a powerful tool in organic chemistry today. In these systems, the combination of multi-catalysts in one system in cooperative and relay manner may enable new transformations through the simultaneous or sequential activation and reorganization of multiple chemical bonds by the metal catalysts and organocatalysts. This concept holds great potential for application to a broad scope of organic synthetic reactions.Here we introduce an unprecedented protocol which directly transformed 2-(2-propynyl)aniline derivatives into tetrahydroquinolines in one operation with excellent enantioselectivity under the relay catalysis of an achiral Au complex and a chiral phosphoric acid. This reaction was considered a consecutive catalytic process consisting of a Au-catalyzed intramolecular hydroamination of a C-C triple bond and a Br?nsted acid catalyzed enantioselective transferhydrogenation. This work not only provides a new entry to tetrahydroquinolines complementary to the known asymmetric hydrogenation reactions of quinolines but also suggests a powerful strategy applicable to the design of transformations beyond the scope of those afforded by either Au complexes or Br?nsted acids alone.Using a similar strategy, we established an asymmetric cyclization of alkynols triggered addition of azlactones catalyzed by a combined catalyst system consisting of a chiral gold phosphate and a phosphoric acid, which results in a new strategy to convert the linear carbon-carbon triple bond functionality to a quaternary stereogenic center. This process provides a unique entry to access conformationally restricted amino acid precursors bearing vicinal quaternary stereogenic senters in high levels of stereoselectivity. In addition, this work first demonstrated that the chiral gold phosphate is able to catalyze highly enantioselective addition of azlactones to enol ethers by using chiral anion to control the stereochemistry.we have disclosed a dynamic kinetic transfer hydrogenation of 2-methyl-2,4-diaryl-2,3-dihydrobenzo[b][1,4] diazepines using phosphoric acids as catalysts. This reaction provided a synthetic approach to access 1,3-diamines in high yields with good to high ee for the major diastereomers and high to excellent ee for minor diastereomers.更多还原