【作者】 何龙；

【导师】 龚流柱；

【作者基本信息】 中国科学技术大学 ， 有机化学， 2010， 博士

【摘要】 含多个手性中心的四氢吡咯衍生物是合成许多天然产物、生物活性物质和手性药物的重要中间体,这类化合物的合成一直是有机合成领域研究的热点。1,3-偶极环加成反应是构成多取代五元环的重要方法之一。更具意义的是,甲亚胺叶立德和贫电子烯烃的1,3-偶极环加成反应是合成四氢吡咯衍生物的一个高效简洁的方法,可以合成结构多样的四氢吡咯环化合物。本文报道了手性布朗斯特酸2.1催化的不对称1,3-偶极环加成反应,详细研究了如:催化剂结构与反应的关系,考察了反应温度,催化剂用量、反应溶剂等反应条件对化学收率和对映选择性的影响。在最佳反应条件下,苯甘氨酸甲酯、苯丙氨酸甲酯都可以取得好的催化结果,得到最高98%ee的对映选择性,同时对于脂肪族的氨基丁酸甲酯也可以取得94%ee的对映选择性。研究还发现双磷酸2.1催化的醛、α-氨基丙二酸二乙酯和端基烯烃的环加成反应也可以得到好的非对映选择性和对映选择性,通过改变反应溶剂,双磷酸2.1催化的醛、α-氨基丙二酸二乙酯和富马酸二甲酯的环加成反应,也可以得到中等的非对映选择性和最高98%ee的对映选择性。通过对反应机理的研究,我们认为双磷酸2.1中的二个羟基氢原子与马来酸二甲酯的二个酯羰基形成氢键,活化亲偶极体;磷氧羰基与叶立德中氮上氢原子形成氢键,活化偶极体。通过对双磷酸2.1的母体芳环和连接链修饰,合成了双磷酸2.12-2.17,并将其应用于环加成反应,得到比2.1差的催化结果。本文还研究了对空气和湿度稳定的手性ZrMS催化剂催化的重氮乙酰苯胺与醛的不对称Darzens反应,得到单一构型的顺式环氧化合物。对于芳香醛可以得到76-96%的化学收率和94->99%ee的对映选择性,脂肪醛可以得到最高98%ee的对映选择性。与钛-联二萘酚催化剂相比,手性ZrMS催化剂催化的反应操作简单,并得到相反绝对构型的顺式环氧化合物,对于合成高对映选择性的顺式环氧化合物,提供了一种与钛-联二萘酚络合物相互补充的一种方法,同时底物规模放大到克级时,反应的对映选择性没有明显的变化。更多还原

【Abstract】 Optically active substituted pyrrolidine derivatives are very important building blocks for the synthesis of many natural products, bioactive substrates and chiral pharmaceuticals. 1,3-Dipolar cycloaddition reactions is an extremely powerful synthetic methodology to access these structural motifs. In particular, the 1,3-dipolar cycloaddition reaction of azomethine ylides(AMY) with electron-deficient olefins is an efficient and straightforward method for the stereoselective construction of pyrrodine compounds.In this paper, we have established a chiral Br?nsted acid catalyzed asymmetric 1,3-dipolar cycloaddition reaction. Studies on the relationship between the structure of Br?nsted acid and the catalytic performance have revealed that Br?nsted acid 2.1 is the optimal catalyst, tolerating a wide spectrum of substrates. Up to 98% ee has been obtained for different phenyl glycine ester under the optimal conditions. The cycloaddition reaction of phenylalaine ester also delivered the products in good yields and with excellent enantioselectivity. We also found that bisphosphoric acids 2.1, showed excellent levels of both diastereo and enantioselectivities for the reaction of aldehyde, diethyl aminomalonate, and terminal alkenes. In addition, the three-component 1,3-dipolar cycloaddition reaction of aldehyde, diethyl aminomalonate and dimethyl fumarate was also successful, affording moderate dr value and high enantioselectivity (up to 98% ee) by using the toluene as the solvent.Theoretical calculations were performed to explore the intrinsic factors for the 1,3-dipolar cycloaddition reaction, revealing that the two carbonyl groups of the dimethyl maleate forms two hydrogen bonds with the hydroxyl groups of the bisphosphoric acid 2.1 and concomitantly, the phosphoryl oxygen forms an additional hydrogen bonds with N-H of azomethine ylides. We also synthesized a series of bisphosphoric acids through structural modification of phosphoric acid 2.1, and the catalytic performance reveals that 2.1 shows superior catalytic efficiency to its structural anologues.In addition, we also developed an asymmetric Darzens reaction of aldehydes with diazo-N,N-dimethylacetamide catalyzd by an air-stable and storable chiral zirconium Lewis acid catalyst, which is formed from 3,3’-diiodobinaphthol and tetrabutoxyzirconium, giving solely cis-glycidic amides in high yields and with excellent enantioselectivity (76-96% yield, up to >99% ee) for aromatic aldehydes and 98% ee for aliphatic aldehydes. In contrast to the reaction using titanium complex of (R)-binaphthol, the current protocol is easier to operate than the titanium complex and thus provides an important alternative to prepare epoxyamides with high enantiomeric purity. The Darzens reaction could be carried out smoothly on gram-scale under mild conditions with a very subtle erosion of the stereoselectivity.更多还原